Basic Configuration

• The AS number on the router eigrp command must match against other routers.
• The network-number on the network command indicates which networks will be part of the same EIGRP autonomous system.
  • This can either be a network number, a subnet, or a specific address of an interface
  • Determines which links on the router to advertise to and which links to listen advertisements on.
• The wildcard-mask is optional. The wildcard bits 0 means to match the bits, 1 means don’t care.
  • If wildcard mask is not used, EIGRP will include the whole classful network of the configured network-number.
  • To illustrate the point:

• In the above table, because no wildcard mask was used in the original configuration, RouterA changes the network command to show classful networks.
• Following is an example using a wildcard mask:

routerA(config)#router eigrp 109
routerA(config-router)#network 10.1.0.0 0.0.255.255
routerA(config-router)#network 10.4.0.0 0.0.255.255
routerA(config-router)#network 172.16.2.0 0.0.0.255
routerA(config-router)#network 172.16.7.0 0.0.0.255

• The example above matches all four interfaces.

The ip-default network Command

ip default-network network-number

• The network-number is considered the last-resort gateway that will be announced to other routers.
• Before the router (on which this command is configured) announces the candidate default route, that network must be reachable by this router.
• The network number specified in the command must also be passed to other EIGRP routers so that those routers can use this network as their default network and set as their gateway of last resort to this network.
  • meaning the network must be EIGRP-derived network in the routing table, or
  • must be generated with a static route and then redistributed into EIGRP.
• Multiple default networks can be configured.
  • downstream routers then use the EIGRP metric to determine the best default route.

Route Summarization

• EIGRP has autosummarization on by default and therefore summarizes on the major network boundary by default. This can be disabled. EIGRP summary routes allows you to summarize on any bit boundaries within the network as long as a more specific route exists in the routing table.
  • Note: Classful routing protocols (RIPv1 and IGRP) automatically summarize routes on the classful network boundary and do not support summarization on any other bit boundaries. Classless routing protocols support summarization on any bit boundary.
  • Distance vector protocols’ drawback has always been the inability to create summary routes at arbitrary boundaries of the network. EIGRP, although based on a distance vector protocol IGRP, added the functionality to do so.
• When configuring summarization on a router’s interface, a summary route is added to the routing table and next hop interface is set to null0 (a directly connected, logical interface)
  • This is to prevent loops by preventing the router from forwarding a packet destined to an unknown subnet from being forwarded to other routers. If the destination subnet is unknown but the packet matches the summary route, the packet is forwarded to null0 and subsequently gets dropped (it goes to the bit bucket).
• An effective summarization design is to have contiguous subnets configured on all interfaces of a router.
• The number of subnets that can be represented by a summary route is directly related to the difference in the number of bits between the subnet mask and the summary mask.
  • The formula to calculate the number of subnets that can be represented by a single summary route is [2ⁿ] where n is the difference in the number of bits between the summary and the subnet mask.
  • for example, if the summary mask contains 3 fewer bits than the subnet mask, eight subnets (2³ = 8 ) can be summarized into one advertisement.
• When configuring summary routes, the IP address of the summary route and the summary mask must be specified.

Configure Manual Route Summarization

• As mentioned above, although EIGRP autosummarizes by default, there are cases you may want to turn it off.
  • One such case is if you have a discontiguous network.
• After you turn off the autosummarization, you can then configure a manual summarization and create a summary route on any bit boundary.

• The parameters for the manual summarization configuration are:
  • as-number – the EIGRP autonomous system number
  • address – the summary address. It does not have to be aligned on Class A, B, or C boundaries
  • mask – the subnet mask for the summary address
  • admin-distance – an optional parameter to configure the Administrative distance (0 to 255).

Consider the following example:

• The figure above shows a discontiguous network (172.16.0.0 -> 10.0.00 -> 192.168.4.0.
• Under the default settings, Router1 and Router2 summarizes routes to the classful address 172.16.0.0. As a result, Router3 has 2 equal routes to network 172.16.0.0. If there are packets intended to any specific router, there is a good possibility that the packets will get lost because Router3 sees the routes to either networks as equal and would load balance between the two.
• In order to prevent this, automatic route summarization should be turned off on both Router1 and Router2 as shown below:

Router1(config)#router eigrp 100
Router1(config-router)#network 10.0.0.0
Router1(config-router)#network 172.16.0.0
Router1(config-router)#no auto-summary

Router2(config)#router eigrp 100
Router2(config-router)#network 10.0.0.0
Router2(config-router)#network 172.16.0.0
Router2(config-router)#no auto-summary

• As a result of the above configurations, the networks will not be autosummarized at the major network boundary and all the subnet routes will be carried into Router3′s routing table.
• An EIGRP router autosummarizes routes only for networks to which it is attached to. Because Router3 does not own the 172.16.0.0 network, it will not autosummarize 172.16.1.0 and 172.16.2.0 it learned from Routers 1 and 2. Router 3 will therefore send routing information about 172.16.1.0 and 172.16.2.0 to the world.
• However, a manual summary route can be configured out of Router3′s s0 interface in order to reduce route advertisements about network 172.16.0.0 to the world:

Router3(config)#router eigrp 100
Router3(config-router)#network 10.0.0.0
Router3(config-router)#network 192.168.4.0

Router3(config)#interface s0
Router3(config-if)#ip address 192.168.4.2 255.255.255.0
Router3(config-if)#ip summary-address eigrp 100 172.16.0.0 255.255.0.0

• For manual summarization, the summary is advertised only if a component (a more specific entity that is represent in the summary) of the summary route is present in the routing table.

• Summary routes have an administrative distance of 5. The administrative distance will only show on the local router performing the summarization by using the show ip route network command, where network is the specified summary route.
• Standard EIGRP routes have administrative distance o 90.
• External EIGRP routes have administrative distance of 170.

Resources

1. Configuring EIGRP – Cisco IOS IP Routing Protocols Configuration Guide, Release 12.4
2. Configuring a Gateway of Last Resort Using IP Commands
3. EIGRP – Summarization

This entry is not an authoritative guide. These are merely notes and rehash of the primary text materials and resources that I use. For a thorough guide of the BSCI course, consider purchasing Building Scalable Cisco Internetworks (BSCI) (Authorized Self-Study Guide) (3rd Edition) by Diane Teare and Catherine Paquet, as well as following the links on the resources section of this entry.

Just thought it was… funny?

Report: IT Admin Locks up San Francisco’s Network

A network administrator has locked up a multimillion dollar computer system for San Francisco that handles sensitive data and is refusing to give police the password, the San Francisco Chronicle reported Monday.

The employee, 43-year-old Terry Childs, was arrested Sunday. He gave some passwords to police, which did not work, and refused to reveal the real code, the paper reported.

The new FiberWAN (Wide Area Network) handles city payroll files, jail bookings, law enforcement documents and official e-mail for San Francisco. The network is functioning but administrators have little or no access.

Childs, who remains in custody, is accused of improperly tampering with computer systems and causing a denial of service, said Kamala Harris, San Francisco’s district attorney, on Monday afternoon.

“The bail has been set at $5 million, and the exposure in this case if he were convicted on all counts would be seven years in prison,” Harris said.

Harris said it’s unknown why Childs tampered with the system. The Chronicle, however, reported that Childs was disciplined recently for poor performance. Childs worked in the Department of Technology for San Francisco, making close to US$150,000 a year, the paper reported.

City officials told the paper that Childs may have caused millions in damage while also rigging the network so that other third parties could monitor traffic, posing a huge data security risk. He is also alleged to have installed a tracing system to monitor communications related to his personnel case.

My (partial) BSCI study schedule is up. It’s just a preview of how it’s shaping up to be. I didn’t publish the whole thing yet because the darn thing will not show up the way I formatted it on excel. It appears that pasting an excel spreadsheet to a wordpress post doesn’t work quite well. I’ve had the same problems with the CCNA schedule. In fact I had it all looking nice and pretty. And everytime I updated it, it just started to get worse and worse.

Anyway, I have a little over half of the 4-month schedule planned out. I’ve had to change it many many times, of course.  I may  even get rid of the table if I can’t get it to look right and just go with the bulleted-style. For now, this will do. I don’t really want to spend so much of my time tweaking this as I’m already way behind in my readings.

All CCNA/CCNP bloggers, where ya at?

In recent days, there’s been a lot of buzz amongst popular CCIE bloggers about the growing trend of CCIE candidates blogging about their experiences. Ethan Banks recently added some new CCIE bloggers on his list and I know he’s been looking for writers to contribute to his own blog as well. Just today CCIE Pursuit summarized some of the previous headlines calling for CCIE candidates to blog about their journeys. IpExpert is looking for bloggers on their new CCIEblog.com domain – and they are giving away excellent prizes to get people to sign up.

I think these are excellent ways to share knowledge and contribute to the networking community as well. In fact reading these blogs is what really gave me a lot of ideas that I incorporate in my own blog. They also serve to inspire me to keep pushing towards my career goals.

But while these expert level blogs continue to increase, I haven’t seen many CCNA/CCNP-centric blogs out there. Once every week or so I scour the internet to find such blogs that can potentially be a source of “information dump” for people like me pursuing the CCNP. And when I refer to information, I don’t just mean facts and figures related to the CCNP subject areas like routing, switching, or anything technology related. I’m also looking for people just sharing about how they feel towards the actual journey itself:

• Are they finding it hard, easy, manageable, etc?
• Do they approach their studies similar to how I approach it.
• Are they spending the same amount of time to certify as I am?
• What kind of real-world experience do they currently have and to what extent does real-world experience minimize the effort needed to pursue their goals?

Essentially, it’s a study of patterns and habits, and ways of doing things. It’s a gauge of where typical is and isn’t. Information and tidbits can be had very easily with all the information that is out there. But to follow a specific person’s journey is a true learning in itself. And I do think it’s a great way to learn.

Just to expound a little bit on what I’m trying to get at: When I was in college, I took a lot of sociology and anthropology classes. When I was learning about how researches studied other cultures/tribes/groups of people, these researches couldn’t just observe them and formulate their own conclusions. They had to live with these people. They followed their every move, their every habits, and participated in their customs. By doing this, we learned why people do things that to others don’t make sense. And we can agree that other ways of doing things can be just as effective as the way we do things.

That’s kinda like how it is with blogging. Technology has gone a long way to bridge people closer. With the popularization of web 2.0 technologies, we are able to experience a whole new way of doing things. I’ve been blogging since late 2003/early 2004 and I found it a very convenient way to interact with my friends and family by sharing with each other happenings, events, images, and other things through this.

So back to my original thought, where are all the CCNA/CCNP bloggers? Make yourselves known if you’re out there. Let us know how you study, how you feel about your journey, and what your goals might be. It’s interesting how so many CCIE blogs are out there when there clearly is a lot more folks running for the CCNP. Is it that CCIE candidates take a more serious effort towards getting their digits than someone who is working on his CCNP? I’d hate to think so. If anything, a strong foundational background of the lower to mid level skills will probably do more to help in preparation for the higher-level certs such as CCIE. Or is it that people just don’t bother with it because the CCNA/CCNP level certs don’t reflect as much “prestige” as trying to acquire a CCIE cert? Who knows! But if you happen to read this and are on a path to getting a CCNA or CCIE, I encourage you to blog about it (if you don’t already do). We get to learn a lot about the characteristics and tendencies of those studying for the CCIE, but there is a huge void about how they got there.

Enhanced Interior Gateway Protocol (EIGRP):

• Is a Cisco-proprietary protocol. It combines the best of link-state and distance vector routing protocols.
• Has its roots as a distance vector routing protocol but adds several link-state features such as dynamic neighbor discovery.
• Is easy to configure.
• Unlike IGRP, it has takes advantage of rapid convergence and guarantee a loop-free topology at all times.

Some of its features include:

• Fast Convergence
  • It uses the Diffusing Update Algorithm (DUAL) for rapid convergence
  • It stores a copy of its neighbors routing table and uses those information to act quickly in case the primary route fails
  • If there is no backup route in the routing table, EIGRP will send a query to its neighbors to find an alternate route. Queries will continue to be sent until a route is found, or it decides that there is no other routes that exists.
• Support Variable-length Subnet Masking
  • It advertises a subnet mask for each destination.
  • Supports discontiguous networks.
• Partial Updates
  • Instead of sending a complete update of the routes, partial updates are sent only when something changes. And it only sends information about the link that changes and not the whole routing table.
  • This allows EIGRP to consume less bandwidth and CPU.
  • Contrary to this behavior, link-state protocols send updates to all router within an area.
• Multiple Network Layer Support
  • EIGRP Supports IP, Appletalk, and IPX.
  • Each network layer uses its own protocol-dependent module to enable support for each.
• Works across all Data-link layer protocols and topologies
  • Unlike OSPF, it does not require special configuration to work across any Layer 2 protocols.
  • Works effectively on both LAN and WAN environments.
  • Supports all WAN topologies
    • dedicated links
    • point-to-point links
    • Non-broadcast multiaccess (NBMA) topoplogies
  • Reliable multicasting is used to form neighbor relationship in multiaccess topologies such as Ethernet
• Sophistacated Metric
  • Allows for unequal metric load balancing – an advantage over IGRP.
  • Unlike IGRP’s 24-bit format, EIGRP’s metric calculation uses 32-bit format (IGRP metric multiplied by 256)
• Use of Multicast and Unicast
  • Instead of broadcast, unicasts and multicast can avoid sending update and queries to user end stations.
  • EIGRP uses multicast address 224.0.0.10

• EIGRP routing information is delivered using IP packets with protocol number 88 in the IP header.
• EIGRP routing process is a transport layer function of the OSI reference model(?)
• Defaults to use automatic route summarization. Manual route summarization can be configured instead.
• Support creation of supernets and aggregated blocks of addresses.
• Supports both hierarchical and non-hierarchical IP addressing.

Underlying Process and Technologies

EIGRP uses four underlying technologies to define its operation:

1. Neighbor Discovery/Recovery Mechanism
   • Allows routers to discover other EIGRP enabled neighbor routers that are directly connected to each other.
   • With the use of low-overhead and periodic hello messages, each routers are able to discover when neighboring routers become unreachable or inoperative.
   • As long as hello messages are received, neighbors assume that each neighbor is functioning and they can exchange routing info.
2. Reliable Transport Protocol
   • RTP is responsible for making sure that EIGRP packets are guaranteed to be delivered. It also controls the correct order by which they are delivered.
   • Allows routers to transmit mixed multicast and unicast packets.
   • To allow for efficiency in transmission, only certain packets are transmitted reliably.
     • For example, a multicast transmission through Ethernet does not require a reliable transmission of packets to all neighbors individually. So EIGRP sends a multicast hello packet but indicating on the packet that the receiver need not acknowledge receipt.
     • Other types of packets, such as updates, do need acknowledge that they are receive, so EIGRP sends the packets containing an indicator letting the recipient know that it needs to be acknowledged.
   • RTP allows for sending packets quickly even when unacknowledged packets are pending. This helps with fast convergence time.
3. DUAL finite-state machine
   • DUAL is the mechanism that makes the decision for all route computations.
   • It tracks all the routes advertised by all the neighbors and uses distance information (metric or cost) to find the most efficient and loop-free route to a destination.
4. Protocol-dependent Modules
   • Responsible for supporting the use of IP, AppleTalk, IPX for specific Network Layer implementations of EIGRP.
   • Each of the above mentioned Network layer protocols has its own EIGRP module and operates independently of each other.
   • For example, IP EIGRP is responsible for handling EIGRP packets encapsulated in IP while at the same time IPX-EIGRP handles packets for IPX. IP-EIGRP parses EIGRP packets and informs DUAL of the new information that was received. DUAL makes routing decisions that is stored in the IP routing table. IP-EIGRP also redistributes routes learned by other IP routing protocols.

EIGRP Terminology and Operation

• Neighbor Table
  • Stores information for new neighbors including the:
    • Neighbors address
    • The interface through which that neighbor can be reach.
  • Comparable to the neighbor database used by link-state routing protocols.
  • Similar to the link-state protocols, it ensures bi-directional communication between directly connected neighbors.
  • A separate neighbor table is created for different network protocols. Example:
    • IP neighbor table
    • IPX neighbor table
    • AppleTalk neighbor table
• Topology Table
  • Each neighbor routers sends to each other updates about routes each routers know about. These updates are stored in the topology table.
  • In other words, each router stores its neighbor’s routing tables in its EIGRP topology table.
  • The rule followed by all distance vector protocols is that if a neighbor is advertising a destination, use that route to forward packets.
  • Each network protocol has its own topology table (IP, IPX, AppleTalk)
• Routing Table
  • Holds the best routes to each destination and is used for forwarding packets.
  • The best route (known as successor) is presented to the routing table to be used for forwarding packets
  • If there are different routing sources involved and more than one route is found, the administrative distance is used to determine which route goes on the routing table.
  • by default, a total of 4 routes to the same destination with the same metric can be added to the routing table. The router can be configured to take up to 16 routes per destination.
  • Each network protocol has its own routing table as well.
• Feasible Distance
  • The lowest cost distance from this router to the destination.
  • This is the cost between this router (the local router) to the destination.
  • The sum of the cost between this router (the local router) and the next-hop router plus the cost between the next-hop router and the destination (advertised distance) is the feasible distance.
• Advertised Distance (aka Reported Distance)
  
  • Distance to a specific destination as advertised or reported by its neighbor
  • The cost between the next-hop router and the destination
• Successor
  • The route for a particular subnet with the best metric.
  • It is the neighboring router that has the lowest-cost path to a destination – which also means it has the lowest FD.
  • You can have multiple successors if they have the same FD.
• Feasible Successor
  • A next-hop router that serves as backup to the current successor.
  • The condition is that the said router’s AD (or RD) is less than the FD of the current successor route.
  • Once the feasible successor is selected, they are placed in the topology table. If a change in topology occurs which requires a new route, DUAL looks for the feasible successor and uses it as new route.
  • If no feasible successor exists, DUAL recomputes to find a new successor.

Populating EIGRP Tables

Neighbor Tables

• Contains lists of directly connected routers running EIGRP with which the router has an adjacency.
• The list includes the address of each neighbor and the outgoing interface of the local router to reach that neighbor.
• The neighbor-table entry also includes other information used by RTP:
  • In order to match acknowledgement with data packets for reliable transmission, sequence numbers are used. The last sequence number received from a neighbor is recorded to detect out-of-order packets.
  • A transmission list is used to queue packets for possible retransmission on a per-neighbor basis.
  • Round-trip timers are kept in the neighbor-table entry to estimate an optimal retransmission interval.

Topology Table

• Contains list of all routes learned from each EIGRP neighbor.
• Each neighbor sends a copy of its IP routing table to their connected neighbors. Once received, each router will story these tables on their respective EIGRP topology table.
• These topology tables maintain the metrics advertised by the neighbors (the AD/RD) as well as its own metric to reach the destination via these next-hop neighbors (their FD).
• To display all the IP entries in the topology table use the command:
  • sh ip eigrp topology all-links
• To display on the successor(s) and the feasible successor(s), use the command:
  • sh ip eigrp topology
• Updates occur when a directly connected route or interfaces changes, due to a failure or others, or when a neighboring router reports a change to a route.
• There are two states for a topology table entry:
  • Passive – a state when there is no computation being performed by the router. This considered a stable state.
  • Active – occurs when there is a change in the topology and the router needs to perform a recalculation (looking for a new successor, for instance.)
    • With the availability of a feasible successor, a destination never has to go into the active state.
    • Recomputation occurs in the event a successor goes down and there is no available feasible successor.
    • The recomputation starts by sending a query packet to each neighboring routers. The neighboring router sends a reply with a route to the destination. If a route does not exist another query packet is sent. At this instant the route in the neighboring router remains in active state. During this state the router cannot change the routing table information for the destination cannot change. Once all neighbors have sent back a reply packet, the topology table entry for the destination returns to the passive state.
    • Each router then examines its EIGRP topology table and determines the best route and feasible routes to every destination in the network.

IP Routing Table

• List of all best routes from EIGRP topology table and other routing processes.
• When a router examines the topology table, the router compares all the FDs to reach each destinations and selects the lowest FD for those destination and places the route in the IP routing table.

EIGRP Packets

• Hello
  • Used for neighbor discovery.
  • Sent as multicast using address 224.0.0.10
  • Do not require acknowledgment. They carry an acknowledgment number of 0.
• Update
  • Contain route change information.
  • Sent to communicate the routes that a particular router has used to converge.
  • Only sent to affected routers.
  • Updates are sent as multicast by routers after they have discovered a new route and have converged (when the route becomes passive).
  • During the EIGRP startup sequence, updates are sent to the neighbors as unicasts to synchronize their topology tables.
  • Updates are sent reliably.
• Query
  • A query packet is sent to neighbors when a router performs route computation and it does not find a feasible successor.
  • Normally sent as multicast but can be retransmitted as unicast packets in certain cases.
  • Query packets are sent reliably
• Reply
  • Sent in response to a query packet.
  • Sent as unicast back to the router that sent the query.
  • Sent reliably
• ACK
  • Used to acknowledge updates, queries, and replies.
  • They are unicast hello packets.
  • Contain a nonzero acknowledgment number.
  • Does not require acknowldgement.

EIGRP Hello Packets

• EIGRP routers discover other EIGRP routers connected to it through the hello protocol. EIGRP is configured on interfaces on routers and hello packets are sent out through these interfaces addressed to multicast destination of 224.0.0.10. If a router receives a hello packet coming from another router in the same autonomous system (AS), they establish a neighbor relationship (adjacency)
• By default, hello packets are sent out every 5 seconds on:
  • LAN links such as:
    • Ethernet
    • Token Ring
    • FDDI
  • WAN links such as:
    • point-to-point links such as PPP
    • HDLC
    • Frame Relay
    • ATM
  • Multipoint circuits with bandwidth greater than T1
    • ISDN
    • PRI
    • ATM
    • Frame Relay
• On slower interfaces (T1 or less), hello packets are sent out every 60 seconds:
  • ISDN BRI
  • Frame Relay
  • ATM
  • X.25
• The hello interval can be adjusted on a per-interface basis, to change the rate at which hello packets are sent. To change, use the interface subcommand:
  • ip hello-interval eigrp as-number seconds
• Hold-Time interval is the amount of time a router considers a neighbor up or alive without receiving a hello or some other EIGRP packet from that neighbor.
  • The hold time interval is set to 3 times the hello interval.
    • 15 seconds for LAN and fast WAN
    • 180 seconds on slower WAN
  • To adjust the hold time, use the interface subcommand:
    • ip hold-time eigrp as-number seconds
• If the hold time expires without receiving a packet from the neighbor, the adjacency is deleted and all topology entries learned from that router are removed.

EIGRP Neighbors

• The hello and hold-timers don’t have to match for two routers to establish adjacency. Therefore, hello interval and hold-time values can be set independently on different routers.
• In order to solve some addressing issues, secondary addressing can be applied on interfaces. However, because EIGRP traffic uses the interface’s primary address, EIGRP will not build adjacency over secondary addresses. EIGRP packets use the primary IP address of all neighbor routers as their source IP address.
  • In order to form adjacency, the routers’ primary IP addresses must be in the same subnet
  • Additionaly, they must reside in the same autonomous system.
  • Also, their K values (metric-calculation mechanism constants) must match.

Neighbor Table

• Information on the routing tables are built using the information gathered from the hello packets received from neighbors
• The command sh ip eigrp neighbor displays the content of the IP neighbor table.
• The elements on the neighbor table includes:

Router# show ip eigrp neighbors
P-EIGRP Neighbors for process 77

Address          Interface    Holdtime Uptime   Q      Seq  SRTT  RTO

                              (secs)   (h:m:s)  Count  Num  (ms)  (ms)
172.16.80.31     Ethernet0     12       0:02:02  0      4    5     20

172.16.81.28     Ethernet1     13       0:00:41  0      11   4     20

172.16.80.28     Ethernet0     14       0:02:01  0      10   12    24

EIGRP Reliability

• RTP ensures and guarantees an ordered delivery of EIGRP packets to all neighbors. It supports transmission of multicast and unicast packets. To maximize efficiency, only certain packets are transmitted reliably
• Reliable Packets
  • Update packets
  • Query packets
  • Reply packets
  • These packets contain routing information and are are sent reliably – because they don’t go out on a periodic basis.
  • A sequence number is assigned to each packet and an acknowledgment is required for that sequence number.
• RTO Timer
  • Each neighbor maintains a retransmission list that indicates packets not yet acknowledged by a neighbor within the RTO.
  • If RTO expires before receiving an ACK packet, EIGRP retransmit another copy of the packet, up to a maximum of 16 times or until the hold time expires.
• On multi access media where multiple neighbors reside, there could be potential problems if one of the peers does not respond with an ack immediately. The next multicast packets are not sent until every peer have acknowledged the multicast packet the was sent earlier which causes delay on sending packets to those peers that have already sent acknowledgments. To remedy this, RTP resends the unacknowledged packets as unicasts. This allows the transmission of reliable multicast to operate without slowing downs the other neighbors.
• Multicast flow timer
  • Maximum amount of time to wait for an ACK packet before EIGRP starts sending unicast instead of multicast.
  • The RTO determines the amount of time to wait between subsequent unicasts
  • Multicast flow timer and RTO are calculated based on the SRTT.
• Sometimes, the average hold time of 15 seconds (on high speed links) or 180 seconds (on slow speed links) wait time is too slow to wait before determining a neighbor adjacency to be down. Other conditions can override the hold time can be overridden and allows the network to converge much quicker.
  • For example, a slow WAN link to a remote site whose router is flapping and timing out constantly, the hold timers begin counting down from 180 seconds. When the main site sends an update to the remote site and the remote site does not send an acknowledgment, the main router tries to retransmit the update 16 times – sending one update every time the RTO expires up to 16 times. After the 16th attempt, the router resets the neighbor adjancency. This allows faster convergence of the network instead of waiting for the hold time to expire – 16 RTO times could be a matter of milliseconds compared to 180 seconds hold time.

Initial Router Discovery

Consider two routers (Router A & Router B). Router A just comes up on the link with EIGRP configured:

1. Router A sends a Hello packet out all interfaces configured for EIGRP
2. Router B receives the Hello packet from its interface connected to A. B responds by sending an Update packet back to A, containing the routes B has in its routing table. The one exception is that B does not send routing information that it learned through its interface with Router A. Router B also send a Hello back to Router A, at which point a neighborhood adjacency is formed.
3. Router A sends an acknowledgment (ACK packet) back to Router B to let it know that it received all updates.
4. Router A adds the information to its topology table where all other destinations learned from other routers are stored. Each destination lists all neighbors that can get to that destination along with their respective metrics.
5. Router A then sends an update packet to Router B.
6. Router B sends back an ACK.
7. At this point Router A and Router B calculates their successor and feasible successor routes in the topology table and offers the successor to the routing table. The feasible successor stays in the topology table where it waits until it is needed.

Split Horizon

• In its basic premise, split horizon prevents a router from advertising a route out of the interface through which that route was learned.
• Consider the following scenario:
  

• R1 is the hub router and R2 & R3 are the spokes connected to a single multipoint interface on R1 (frame relay)
• In this scenario, EIGRP is used to advertise the networks on each routers.
• However, split horizon is enabled by default on EIGRP therefore R1 will not be able to advertise the network 2.2.2.2 it learned from R2 to router R3. Likewise, R1 cannot advertise to R2 the network 3.3.3.3 that it learned from R3.
• Because R1 learned each of the networks through its interface connecting to R2 and R3, it cannot re-advertise those learned networks back the same single interface.

Route Selection

• A distinguish factor in the EIGRP route selection that is different from other routing protocols is its selection of a primary (successor) and backup (feasible successor) routes. EIGRP calculates a successor and feasible successor and puts them into the topology table. It then takes the success route information and offers it up to the IP routing table.
• EIGRP route types:
  • Internal - routes that originate withing the EIGRP autonomous system
  • External – routes learned from another routing protocol or another EIGRP AS.
  • Summary - routes that encompass multiple subnets.
• DUAL calculates the best route to a destination. To select the best route, it adds up the FD and AD of the neighbor route and the least-cost route is the route that is injected into the routing table. DUAL also makes sure that the path is loop-free. DUAL also calculates the feasible successor route and makes sure it too is loop-free.

Metric Calculation

There are 5 variables that can be used to calculate the EIGRP metric, but it only uses the first two by default:

• Bandwidth – the slowest bandwidth between the source and destination
• Delay – cumulative delay (add all delay values of each routers) along the path.
  

The next 3 are rarely used for calculation because they either result in more calculation or the default values results in them not being used:

• Reliability – the worst reliability between the source and destination, based on keepalives.
• Loading – the worst load on a link between the source and destination based on the packet rate and the interface’s configured bandwidth.
• Maximum transmission unit (MTU) – the smallest MTU in the path.

In addition the the variables mentioned above, the metric calculations for EIGRP factor in some constant weight values. They are:

• K1 = 1
• K2 = 0
• K3 = 1
• K4 = 0
• K5 = 0

The formula is:

Because of the default values of of the K values, the metric above ends up being:

metric = [(1 x bandwidth) + [(0 x bandwidth) / (256-load)] + 1 x delay] x [0/ 0+reliability] x 256
metric = bandwidth + [0] + delay x [0] x 256
metric = bandwidth + delay

• K values are included in the hello packets.
• In order for routers to form neighbor relationship, the K values must match
• Modifying these values is generally not recommended.

Delay and Bandwidth Values

• Delay values are calculated in units of tens of microseconds and is the sum of all delays in the path multiplied by 256.
  • show interfaces command displays delay values in microseconds (vs. tens of microseconds)
• The bandwidth value is calculated using the minimum bandwidth link in the unit of kbps. The formula is (10⁷ / least-bandwidth) x 256
• EIGRP and IGRP
  • EIGRP uses a 32-bit format while IGRP uses 24-bit in representing its metrics.
  • Basically, they both have the same formula, but when integrating IGRP routes into an EIGRP domain using redistribution, the router multiplies IGRP metric by 256 to get the EIGRP-equivalent metric. Inversely, when redistributing EIGRP routes to IGRP routing domain, the router divides each EIGRP metric by 256 to get the proper 24-bit metric.

Routing Table and EIGRP DUAL

• Diffusing Update Algorithm DUAL
  • is the mechanism that decides what information goes in the topology and routing table.
  • process behind route computation
  • tracks all routes advertised by all neighbors
  • uses the metric to select an efficient, loop-free path to each destination, and inserts the choice in the routing table.
• Advertised Distance and Feasible Distance
  • The Advertised Distance (aka Reported Distance) is the neighbor router’s metric to reach a particular destination network. This metric is advertised/reported to their neighbor routers letting them know how far the destination from their perspective. This is the metric between the next-hop router and the destination network
  • The Feasible Distance FD is the metric of the this router to reach a particular network. To get the FD, add the AD/RD of the next-hop router and the EIGRP metric to reach that next-hop router (the cost between this router and the next-hop router)
  • It is important to remember that the FD, not the AD, affects the selection of the best route. The AD is merely a component that is part of the calculation of the FD.
• The Successor Route is the route to the destination network that cost the least. The router inspects all the FDs in its topology table. The least-cost FD to reach a destination network is selected by the router to be placed in the routing table to be used as the successor route to the destination network. The FD of the chosen route also becomes the EIGRP routing metric in the routing table.
• Successor
  • This is the next-hop router that has the least-cost path (the best path) to the destination.
  • It has the lowest FD of all possible paths to the destination.
  • When the router chooses the best path to a destination, it adds the following details to the IP routing table:
  • • The destination network
    • The metric to reach that network
    • The outbound interface to reach the next-hop router
    • The IP of the next-hop router
  • By default, up to four successors can be added to the IP routing table. This can occur if as many entries that have equal-cost FD exist in the topology table.
• The routing table is basically a subset of the topology table. There is more information in the topology table, which includes:
  • Detailed information about each route.
  • Any backup routes.
  • Information used exclusively by DUAL
• Feasible Successor (FS)
  • The router that act as the backup route.
  • They are selected at the same time the successors are identified.
  • They are kept in the topology table.
  • There can be multiple FS routes in a topology table.
  • Requirements to be a feasible successor:
    • Must be mathematically proven
    • The next-hop router must have an AD less than the FD of the current successor route for that network.
  • If a router loses a route, the router looks for an FS in the topology table. If the FS exists, that router is promoted to a successor and added to the routing table. The router never goes into an active state because there is no calculation necessary and the change is immediate.
  • If there is no available FS, the router has to recalculate to find the best route. This is when the router goes into active state.

Resources:

1. Internetworking Technology Handbook – EIGRP
2. EIGRP Technology White Paper
3. Cisco IOS IP Routing Protocols Command Reference – EIGRP commands
4. The EIGRP Neighbor Discovery Process
5. EIGRP and Split Horizon – Chris Bryant
6. EIGRP FAQ – Split horizon
7. EIGRP – Wikipedia
8. EIGRP DUAL Queries, SIA and Stub Routers – Chris Bryant

This entry is not an authoritative guide. These are merely notes and rehash of the primary text materials and resources that I use. For a thorough guide of the BSCI course, consider purchasing Building Scalable Cisco Internetworks (BSCI) (Authorized Self-Study Guide) (3rd Edition) by Diane Teare and Catherine Paquet, as well as following the links on the resources section of this entry.

I guess the coast is clear and I can safely say that this blog is now a CCNP blog. That’s kinda cool. But I can’t wait until this becomes a CCIE blog . But as you can see on the description just under my title heading, this will be a CCNA/CCNP blog, maybe for a long time to come.

I realized yesterday while studying for the EIGRP portion of the BSCI that I have been referencing my CCNA books just as much as my current study materials. So far the book I’m reading provides a lot of information building up on what I’ve learned on EIGRP. I wrote in the past that I had some trouble with EIGRP during my CCNA studies. But that might have been due to external circumstance rather than a reflection of the difficulty level of the material. In other words, I might have been having a bad week during the time I was studying EIGRP. But looking back, I find that the CCNA study materials are just as valuable to my current studies as much as my other other books. So I’m sure that a lot of what I am working on will still be relevant for CCNA and vice versa – as it should.

This past week has been pretty hectic. I’ve only read 20 pages of the study guide since I began the section on Monday. To put it in perspective, however, I’ve also reviewed the Odom book, researched a lot of resources from the Cisco DocCD, and googled other related topics. On top of that, I bought a new desk (a $90 desk that takes up almost half my room) and spent an equivalent of two study sessions putting it together. But despite only having read 20 of the 90 pages on the EIGRP section, I’ve already built up a huge study notes filled with juicy details on EIGRP. I found that the study guide tend to repeat materials that have already been covered a few pages earlier. Smart people might find it annoying or unnecessary but I personally think it’s a good thing because it helps hammer in the idea – good for people like us who have short attention span

Where the heck is the study schedule you promised to publish last week?

Patience grass-hoppa! It is on its way. I found it challenging to put together this time because of several reasons. One is that the new study guide has a different format and organization than I was used to when using Wendell Odom’s exam preparation guides. I had to acquaint myself to the whole organization of the book to make sure I’m setting an appropriate pace for my readings. That is, I I’m trying to avoid scheduling a 150-page reading assignment one week and the next week, I’m only reading a 50-page section.

Secondly, there’s another one involved. It gets complicated when there’s another one involved. Yeah, I also bought the lab portfolio book. Whereas before when I would make up my own CCNA lab based on the examples given on the same book I was reading, now I have a separate 500-page book just for labs. So figuring out where to squeeze it in the schedule is a bit challenging. Plus I didn’t realize there are detailed lab exercises on the study guide as well. So that has to be taken into account also.

Thirdly, I decided that I would try out the first few weeks of my schedule and see how it works out before I decide i need a complete overhaul. Because of the different scenarios I didn’t take into account, I might have to prolong my study schedule. Plus, I did not give myself any breathing room in terms of spacing out my schedule. For instance, I schedule this whole week, July 7-13, to study EIGRP. But I forgot that my wife scheduled a mini-vacation for us this weekend to San Diego. So that’s at least 8 to 10 hours of studying that is not going to happen. That means EIGRP might have to eat up some OSPF time. Meaning OSPF will have to eat up some other topic’s time. It’s a vicious world out there!

I’ve experienced my first missteps this weekend when I did not study at all. Something about the holidays would not let me concentrate on studying as I continuously get distracted every time I make an attempt to crack open the book and get my notepad ready.

I haven’t even started on my study schedule yet. This is starting to look bad. I wanted to get a good start on my studying so that I can end strongly. The amount of time it will take me to get on a roll could significantly push me back on my schedule – or not! It depends on my motivation. And I still feel motivated. It’s just that this weekend, the call of R&R was a stronger force that I couldn’t just ignore. For instance, I woke up yesterday (Sunday) at 6am and went to church with my family. We did some grocery shopping after and got home at 9. I was getting ready to study, but guess what I did. I slept from 9 to 12. All that precious time lost on unnecessary, but much desired, sleep. The rest of the day was spent with family, friends, and TV.

On other personal reasons, something I (re-)read this weekend reminded me of the purpose for doing all this and who I’m doing it for. I was forced once again to step back and look at the bigger picture and be reminded that while the present continues to elapse, we should try not to outrun it. I had to just slow down for one bit and let it catch up. It’s one thing to look out for the future. It’s another to live in it. The same goes for the past.

Today, however, we shall get to know EIGRP on a deeper and personal basis. It will become my best friend by the end of this week – at least until OSPF replaces it next week.

Converged Networks

• A network where all types of traffic such as data, voice, and video coexist.
• Different types of traffic include:
  • Voice and video – IP telephony, and other applications such as video broadcasts and conferencing
  • Mission-critical Traffic – for example, patient records at a hospital.
  • Transactional traffic – related to traffic generated from database interactions (e-commerce, for example)
  • Routing Protocol Traffic – RIP, EIGRP, OSPF, IS-IS, BGP, etc.
  • Network Management Traffic – such as traffic for network monitoring and other information about the network.

Cisco Intelligent Information Network (IIN)

• A Cisco strategy that addresses how the network handles traffic for business priorities. It is considered an alternative to QoS. It integrates network and application functionality.
• Built on top of the Enterprise Composite Model
• It has three phases:
  1. Integrated Transport – consolidation of data, voice, and video transport into a single, standards-based, network module.
  2. Integrated Services - virtualized resources. Example, an Integrated Services Router (ISR).
  3. Integrated Applications – making networks “application-aware”.

Cisco Service-Oriented Network Architecture Framework

• The Cisco SONA is an architectural approach to connect Network Services to Applications to enable Business Solutions.

• SONA framework’s three layers:
  • Network Infrastructure Layer – the layer where all the IT resources are interconnected. These resources are located in various places in the network. The objective of this layer is to provide connectivity, anywhere and anytime.
  • Interactive Services Layer – allocates resources to applications.
  • Application Layer – includes business applications and collaboration applications. The objective of this layer is to meet business objectives and achieve efficiencies by leveraging the interactive services layer.

Cisco Enterprise Architecture

• Cisco Enterprise Campus Architecture – combination of intelligent switching and routing with tightly integrated productivity-enhancing technology, such as IP communications, mobility, and advanced security. It provides high availability through solid multi-layer design, redundant hardware, software features, and failure recovery.
• Cisco Enterprise Data Center Architecture – supports requirements for consolidation, business continuance, and security. Supports emerging service-oriented architectures, virtualization, and on-demand computing. Redundant data centers provide backup. Network and devices provide server and application load balancing.
• Cisco Enterprise Branch Architecture – extends services to remote locations or branch offices.
• Cisco Enterprise Teleworker Architecture – delivers data and voice to the home office.
• Cisco Enterprise WAN Architecture – distribute voice, data, and video in a converged platform over large geographic areas.

Cisco Hierarchical Network Model

• Access Layer - user access to the network and assigning them to VLANs. Avoid implementing network policies here to avoid complexity, costs, and slow down of devices.
• Distribution Layer – aggregates the wiring closets and uses the switches to create functional separation of workgroups and networks. Also aggregates WAN connection at the edge of the campus. Act as intermediate devices that route them between VLANs. Also used to apply policy-based connectivity, such as firewall or QoS.
• Core Layer (aka Backbone) - high-speed backbone designed to switch packets as fast as possible. It is not a good idea to implement traffic policies here as well as it would slow down the devices, which goes against its purpose to move traffic quickly.

This older hierarchically model lacked some features to address several issues such as:

• Implementing redundancy
• Addition of Internet access and security
• Accounting for remote access
• Locating workgroup and enterprise services.

The following model addressed those issues.

Cisco Enterprise Composite Network Model

A newer design compared to the older Cisco hierarchical model. It expands from the older model by making some specific recommendations about how and where certain network functions should be implemented.

• Enterprise Campus – it contains the following components:
  • Building – houses the access switches and end user devices
  • Building distribution – includes the distribution switches
  • Core – the campus backbone that provides high speed access between buildings
  • Edge distribution – interface in between the Enterprise Campus and the Enterprise Edge
  • Server farm – the campus data center
  • Management – management functionalities such as monitoring logging, security, etc.
• Enterprise Edge - connects the enterprise campus to the WAN. Includes the following components:
  • E-commerce – network components that provide e-commerce functionality such as online ordering system.
  • Corporate Internet – provides internet services and access.
  • VPN and Remote Access – where remote VPN access from remote users terminate
  • WAN – provides connectivity to remote sites.
• Service Provider Edge – includes:
  • ISP – services the internet connection
  • PSTN – non-permanent connections such as dial-up, analog phones, cell phones and ISDN
  • Frame Relay, ATM, and PPP connectivity – permanent connections to remote locations.

Routing and Routing Protocols Within the Enterprise Composite Network Model

The rest of this preparation will focus on different IP routing solutions that is an integral part of designing a network.

Resources:

1. Building Scalable Cisco Internetworks (BSCI) (Authorized Self-Study Guide), Third Ed.
2. CCNP BSCI Official Exam Certification Guide, Fourth Ed.
3. SAFE Blueprint
4. Cisco Service-Oriented Network Architecture (SONA)
5. SONA Integrated Network Services At-a-Glance (Overview)

This entry is not an authoritative guide. These are merely notes and rehash of the primary text materials and resources that I use. For a thorough guide of the BSCI course, consider purchasing Building Scalable Cisco Internetworks (BSCI) (Authorized Self-Study Guide) (3rd Edition) by Diane Teare and Catherine Paquet, as well as following the links on the resources section of this entry.

Well, I didn’t wait too long to get started on the BSCI track. I wanted to take advantage of the steam I’ve built up during the last month reviewing for the CCNA exam. I passed the CCNA on Saturday, June 28th, and I began hitting the BSCI books on Monday – two days after.

I started getting excited for the BSCI track midweek last week when I received my first two books (the Study Guide and Lab Portfolio). It even came to a point where having those books on my desk whilst I studied became a distraction, as I couldn’t put it down, browsing through the chapters.

So far I have read two chapters from the Cisco Press Study Guide. Lookout for upcoming study notes.

Here are the materials I’ll be using for my studies:

1. Building Scalable Cisco Internetworks (BSCI) (Authorized Self-Study Guide), 3rd Edition -This will be the primary text book I will be basing my study off. I chose this based from opinions from the Techexams.net forums. They seem to be favoring this one over the Official Exam guide because of it’s more thorough approach. I guess we’ll find out.
2. CCNP BSCI Official Exam Certification Guide, 4th Edition – I decided to purchase this as well since it is the “Official” Exam guide after all. I will use the outline from this book about what I need to learn and fill in the meat using the Self-Study Guide.
3. CCNP Building Scalable Internetworks (BSCI 642-901) Lab Portfolio (Cisco Networking Academy) – Not a lot of people seem to have much experience with this. But because I don’t know any better, I’m willing to put this to the test and see how well it prepares me.
   
4. Dynamips/Dynagen – this has been an invaluable resource for me. I’ve used this roughly about 95% of the time when doing lab practices. The other 5% was done on my real equipment, mostly when doing switching technology labs.
5. CBT Nuggets – Although I like Jeremy a lot, this is a huge maybe, primarily because of the price. I’m gonna have to think hard on this because I really like this product.
   
6. Practice Exams – I’m still not sure which one to use. The study guide does not have one and I haven’t received the Official Cert book yet. The latter is supposed to have a test engine that comes along with it. I’m assuming it’s similar to the Boson engine in Wendell Odom’s book. Those really proved to be tough questions and I believe prepared me pretty well for the exams. If it not, I’ll have to find other alternatives. Transcender, perhaps?
   
7. Other supplemental resources such as PDFs, Cisco DocCD and the mighty google!

Daily schedule

I plan to follow my old CCNA schedule as it seems to have worked quite well for me. So far I like it and my family agrees with it. If things change or I start to get bored with it, I’ll probably devise a different schedule.

Weekdays

6:00am – 6:30am Wake up
7:00am – 8:30am Study
9:00am – 6:00pm Work
6:30pm – 9:00pm Family time
9:00pm – 11:30pm Study

Weekends

Weekends will be a little bit more flexible with times interchanging around. But to give an idea, it should look something like this:

Saturday
7:00am – 7:30am Wake up
7:30am – 9:00am Do what people do on the weekends*
9:00am – 11:00am Study
11:00am – 3:00pm Do what people do on the weekends*
3:00pm – 5:00pm Study
5:00pm – 9:00pm Do what people do on the weekends*
9:00pm – 12:00m Study

Sunday
Pretty much the same except the family and I wake up at 6am to be at Church by 7am. We are home by 8:30am so the fun begins all over again.

*Sometimes we go out to visit family and friends. But I always bring a book with me and my iTouch with the whole ICND2 CBT Nuggets on it. If I get CBT Nuggets again, I plan to do the same.

So there it is. Coming up before the end of the week, I will have finished my official study schedule and everything will be in place again. Just like old times.

I’ve got to say it’s been quite a blast the last few days. With the amount of attention I’ve received on my blog, forums, and personal emails, you’d think I had passed the CCIE exam. I’ve received an equal amount of congratulatory comments from bloggers who I admire and whose pages I frequent, as well as others I’ve never heard from before. And these are coming from people who have been in this field much longer than I have. They are more knowledgeable, more experienced, and accordingly, are in much respectable places in their respective fields. Then there are others who are my “equals” . They are the ones who are on the same boat as I am, sharing in my struggles and my triumphs, and will continue to do so as long as we stay in the same paths.

When I started with this blog, my first inspiration was CCIE Candidate. Then from there I discovered CCIE Pursuit, CCIE Journey (notice the trend) followed by others on their blogrolls. But those big 3 were my first inspiration. The only problem was, much of the contents in them were not applicable to my level of knowledge. So I took what I could from those blogs and tried to get what I could. And what I discovered from reading their personal accounts was that even though the technical contents in those pages were a little bit over my head, the realness of their pursuit, or journey – pun – were as tangible and real as mine. It didn’t matter that these guys were running for their CCIEs and I was running for CCNA. Whatever level we were running at, we still had to put a lot of effort in what we wanted to attain. A baby just learning to walk exerts a lot of effort just as much as Kobe Bryant (I’m a fan , So Kobe haters, give me my moment!) practicing to perfect his jump shots. Sure the kind of focus and the amount of determination is different. But nevertheless, it is both hard and painful for both. So I was able to identify with these blogs and use them as my motivation.

Before this blog was started, I thought to myself, there must be others out there documenting their experiences and are at least in the same league as I am. Around that time I have already decided to pursue the CCNA and change my current stagnating career. So I scoured the Internet in hopes of finding blogs that are at the beginner or intermediate level. Unfortunately there were not as many. And whatever ones I found where either outdated or insufficient. So, inspired by CCIE blogs I have read so far, as well as for other reasons, I decided to start my own. I was not entirely new to blogging. I have kept a personal blog since early 2004, that until recently, have taken the back seat in favor of this one.

My first goal for the blog was pretty basic. That is, to keep a journal of my studies and document my notes ala CCIE Candidate. When I started reading Ethan’s blog, I was convinced that it would be a very effective method of studying. Most of you know the result of his hard work. Some of the benefits I saw in following that format were:

• Obviously, it’s a great way to take notes and make it into a nice bulleted format that you can easily read and peruse.
• It forces you to examine what you are writing because you cannot just write anything that does not make sense.
• Committing to update my blog regularly forces me to read. Duh!
• It’s an excellent way to keep everything organized. I can categorize my posts so that all related topics and technologies can be sorted to display on one page.

There are also other benefits that I did not originally intend to come out:

• By adding a “print post” module, I was able to print out a bulleted reference of each chapters during my review. It was portable and easily available for light review, as opposed to carrying a book.
• I’ve had at least five people in the last week telling me via email, comment, or IM, that they’ve used my notes to supplement their own studies.
• By having my blog published out on the internet and making my presence known, more and more people with blogs similar to mine started to contact me and let me know they themselves are out there. That was a pleasant result as it satisfied my goal of finding comparable materials as mine. Okay, so this point is a benefit that I intended to happen. But I didn’t have the control over the results when I was just starting out.
• It’s a great side effect to have people all over the world sharing, discussing, and collaborating with you. It lets them know that there are others out there doing the same things, aspiring to attain the same price, and working hard just as you are. It breeds inspiration, motivation, and respect.
• It’s a good feeling to know people care. Okay maybe they don’t. But at least they’re interested. Because of our curios nature, we tend to want to know how others do things and how others are doing. Reading other people’s blogs somewhat satisfies that curiosity. It helps those who are otherwise lost or needing some kind of direction. It does me, at least.
• We are a glutton for information. And that is usually good. Maybe not all the time, but, usually. Whatever information I put out there, others come back with better and helpful ones.
• Friends. Maybe they’re not the ones that you tend to hang out with on Friday nights during happy hour and discuss the rigors of the past week. But nonetheless, I’ve met people through this medium and the online community in general that I can share things with and ask about things relative to our profession or careers.
• Comments! I like comments. They give me the warm fuzzies!

I’m very excited about where my career can take me. I think I’ve waited long enough to buckle down and get something going for my professional career. The amount of knowledge is so abundant. There is no possible way to know everything. Through out our career we will meet people much smarter than we are and know more things that we coudn’t have imagined possible. And with the ever changing topology of the connected world, the increasing bandwidth with which one can reach another on the other side of the world, there is no reason to be cooked up in your room, buried in your books, and learn from such a limited medium. After all, its people that create knowledge, people discover knowledge, and people disseminate knowledge. And they are out there. Share something with the world, they are bound to share something back.