CCIE # 23664: Head over to Cisco Learning Blog and drop your congratulatory comments for passing the lab.

I’ve been following his blog since the early part of last year. Thumb through some of his posts and experience some of his early struggles with self-doubt, an addition to the family, and work-load. It’s a nice account of persistence and hard-work paying off.

As for me, posts are on hold as I’m preparing to take my BSCI exam in a couple of weeks. But if you’re just dying to know what I’m doing and your day is not complete without me   follow me on twitter and route my world 140 characters at a time…

I just LOL’ed on that last part.

The game of basketball is a funny thing. When you are on the court, you and a team of foul-mouthed, rough brutes try to best another team of equal ferocity. In the heat of the moment you sometimes get carried away and let all inhibitions loose. Funny thing about it is that after the game, all that display of machisimo and warrior mentality is quickly suppressed back to its dormant state. Everyone is back to their refined, “responsible-citizen” persona.

I had a basketball game last night, in a league I’ve been playing in for the last few years. I sorta got into a little elbowing match with another player. He was going after a loose ball and I “sorta” held him so that I can gain an advantage on getting the ball first. Rightfully so, the ref called a foul on me and I conceded knowing full well that I committed the infraction. The opposing player, however, did not appreciate me holding him and from then on, he made it a personal mission throughout the game to “express” his feelings towards me. Every chance he got, he tugged on my jersey (one time, so hard that it ripped a seam), elbowed me in the back whenever I posted him up, and talked trash to try to get into my head.

Of course, I returned the favor.  

The point  isn’t really about  barbarism or heroism on the court (or the field, if you like football). It really is about knowing your place at the right time and the right moment. The opposing dude and I were going at it for the duration of the game. But we also realize that this is a game. Just a game. This has nothing to do with what life is about or what the outcome of the game has to do with you in the real world – they won by the way. We may try to get the better of each other through intimidation, aggressive play, or pure skill. But in the end, we are all the same and equal.

After the game I went into the restroom to wash up and change. The same person with whom I was scuffling with just earlier entered the rest room while I was… well doing what most do when in the restroom :) After a brief moment of silence, we just started talking like we were old friends. As if nothing ever transpired between us just moments earlier.  There was no “I apologize I was a little rough out there” or “my bad for introducing my elbow to your face” or “you suck”. There was an unspoken code of conduct that we just instinctively understood.

What the hell am I talking about?

I’ve been getting a lot of opportunities to interact with different engineers (networking, Cisco, etc) in my profession with whom I hold certain admiration for – via twitter, blogs, etc. These are folks who have greater experience than I; some even CCIEs. These are people who I want to be like someday – like that 80s jingle, “I wanna be like Mike”. The more I get to interact with them the more I realize their humanness and that there is not much that separate us outside of our profession. They may be a whole lot better than I in maximizing efficient BGP routes and configuring prefix filtering. But in the real world, there is an understanding between us engineers that what you know in your profession doesn’t make you any better than the next. We all discuss things like cars, movies, the weather, etc like nothing separates us despite our paygrade or skill level. It could be intimidating to even talk to them or ask them question sometimes for fear of sounding stupid. But take away BGP, take away OSPF.. or IS-IS or anything networking… and we’re all the same scared and unsure people trying to figure out the next step.

It’s kinda like basketball.

Using the Hello protocol, there is a series of exchanges that routers go through in order to establish relationship when OSPF is initilized. I’d like to go through some of this steps using examples from a lab environment, and watching some debug output in the process.

To start, here’s the setup for the exercise:

Figure 1: A simple topology

Dynamips .net Config:

# OSPF Neighbor Exchange Lab Topology
autostart = False
ghostios = true
sparsemem = true

[localhost]

   [[7200]]
        image = \Program Files\Dynamips\images\C7200-JK.BIN
        # On Linux / Unix use forward slashes:
        # image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
        npe = npe-400
        ram = 96
        ghostios = True

   
    [[ROUTER A]]
        Fa0/0 = B Fa0/0
        model = 7200
        console = 2001

    [[router B]]
        model = 7200
        console = 2002

Down State

Figure 2: Router A – interface added to OSPF

• When the router is enabled on the LAN, it starts in the Down state and starts sending out hello packets to multicast address 224.0.0.5.
• When in Down state, it doesn’t mean that the interface or router itself is down. It’s just that it hasn’t received any Hellos from any neighbors.
• When an interface is enabled on OSPF, it starts sending out Hello packets to multicast 224.0.0.5 as seen in the figure above.
• Notice also that after sendnig Hello packets 4 times (40 seconds) and not finding an OSPF neighbor, it takes it upon itself to elect itself as a Designated Router (DR) for that LAN segment.

Init State

• The init state indicates that a router sees HELLO packets from the neighbor, but two-way communication has not been established. A Cisco router includes the Router IDs of all neighbors in the init (or higher) state in the Neighbor field of its HELLO packets. For two-way communication to be established with a neighbor, a router also must see its own Router ID in the Neighbor field of the neighbor’s HELLO packets.

Figure 3: Router B turns on OSPF on Fa0/0

Figure 4: Router A Goes to Init State

• At 4:43:11 PM, Router B’s Fa0/0 is enabled for OSPF. Almost immediately it starts sending out Hello packets.
• Within a few tenths of a second (at 4:43:17) Router A receives a packet from Router B with its database summary.
• Router A also transitions to the Init state, indicating that although it has received something from Router B, nowhere in those packets is Router A’s Router-ID.
  • Remember, in order for the relationship two transition to the next level (two-way state), the receiver must receive a Hello from the other neighbor which contains its (Router A’s) own Router ID.
• However, aside from needing to receive its own Router-ID in the neighbor field of the neighbors Hello packet, receiving a DBD from the neighbor also puts the state into a two-way state.
  • Looking at the output in figure 4, it confirms that Router A did receive a DBD from Router B.

Two-way State

• In order to attain the 2-way state, a bi-directional communication has to be established between two routers.
  • That means that each router has seen the other’s hello packet.
• When the router receiving the hello packet sees its own Router ID in the received Hello packet’s neighbor field.

Figure 5: Router A in Two-way State

Figure 6: Router B in Two-way State

• I mentioned earlier that receiving a DBD from the neighbor puts the state in a 2Way.
• In this particular example, Router B sent Router A a DBD as soon as it came up (see figure 4) and within milliseconds, Router A went from Init state to a 2way state.

DR Election

• At the end of this state, DR and BDR elections also occur:

Figure 7: Router A – DR Election

Figure 8: Router B – DR Election

• Recall that the router with the highest OSPF priority on a segment will become the DR for that segment.
  • In this case, the OSPF priority is not modified therefore they remain tied at default value of 1.
• In case of a tie, the following Router-ID criteria is followed in order of highest priority (#1 being the best):
  1. Statically configured Router-ID using router-id command.
  2. Highest loopback interface.
  3. Highest active interface.
• In the figures above, none of the provisions just mentioned are actually used. In fact, notice that Router A is the DR despite having a lower IP address.
  • To determine why, look back at when the neighbor exchange started. On the very first figure (figure 2) Router A has established itself as the DR when there were no neighbors up at the time. A DR will not give up its status even if a new interface with a higher priority in its Hello packet comes up. So even though Router B with better priority comes up, it will not preempt the already established DR.
  • You can change this by reloading the router or if the OSPF routing process restarts.

Exstart State

• If the routers involved in the neighbor process are connected on a point-to-point link, the routers become Full after exchanging Hellos.
• On Ethernet links, after the DR and BDR election has been established, a master-slave relationship is formed.
  • The router with the higher router-id becomes the master and initiates the exchange.

Figure 9: Router B – Exstart

Figure 10: Router A – Slave

• Notice that even though Router A is the DR, it doesn’t necesarrily become the master. Remember that the DR/BDR election can take place using a higher priority configured on the router. Or in this case, because Router A was elected a DR first, despite having a lower router ID.
• Router B becomes master because it has a higher router-id regardless of who the DR is.

Exchange State

Figure 11: Router A  – Exchange

Figure 12: Router B – Exchange

• Notice in the figures above that  OSPF routers exchange database descriptor (DBD) packets as they tranisition to the Exchange state.
  • DBDs contain link-state advertisement (LSA) headers that describe the contents of the LSDB.
• Each DBD packet has a sequence number which can be incremented only by master. These
• Notice also that the routers send link-state request (LS REQ) packets. Once received the router sends link-state update packets (which contain the entire LSA) to fulfill the requested information.
• The contents of the DBD received are compared to the information contained in the routers link-state database to check if new or more current link-state information is available with the neighbor.

Loading State

• This is when the actual exchange of link state information happens.
• Link State requests are sent based on information provided by the DBDs -  information such as outdated or missing LSAs. The neighbor then sends the requested information back contained in Link State updates (LSUs).
  • All LSUs need to be acknowledged.

Figure 13: Router A: Loading-Full State

Figure 14: Router B: Loading-Full State

Full State

• Routers achieve Full neighbor adjacency at this state. Network and router LSAs are exchanged and router databases are fully synchronized.

If you notice one of the new tabs right under the heading, I added a new “Archives” plugin to give a nice high level view of all the posts I’ve written. I saw the plugin from a wordpress blog and thought it was cool. Setting it up was easy enough – just download, install, and reference the right code to get it all going.

If you’re interested on adding this to your wordpress blog, just follow the link: http://www.viper007bond.com/wordpress-plugins/clean-archives-reloaded/  -  the least I can do for a free plugin.

Some of my readers may have already seen the following and I’m sure has been posted in many a Cisco blogs. But just to change the atmosphere a little, I thought I’d inject a little humor – especially with all the serious studyage going on – and revisit a classic thread on GroupStudy. 

This was posted on GroupStudy a while back and got some pretty funny responses.  As if the post itself wasn’t entertaining enough, some responses were equally hilarious (follow the link to read the subsequent comments).

Subject: Another New One
From: "Hiriam Masheed Nuwalla MCSE+I" <gs@xxxxxxxxxxx>
Date: Thu, 22 Mar 2007 08:52:55 -0600

Hi Group,

I just complete my MCSE+I and now I have need for CCIE. I have joined group
because I must have CCIE in 30 days, maybe I can wait for 45 days, but no
longer. I want to finish before May starts, for I have futbol league to play
in then.  If I get the CCIE in 30 days, then maybe I try for a second in the
next 15 days. I need to get CCIE so I can make a bigger money. I hear this is
a good group for to join.

The MCSE have many more tests so I think CCIE may not be as difficult as I
hear. One day I pass two exams, one right after another for the MCSE. This is
also "Expert" level certification, just like CCIE. Some people may not know
this, but a Windows server can be setup like a router. I have done this many
times. I have very high IQ and can study sometimes 2 - 4 hours without a
break.

I see a question about a subnet mask. Is it necessary to know the subnets
other than a 255.255.255.0? I have set these networks up many times, and am
almost an expert with them. One time there were 4 of these networks all
working through a windows box, and I did this in less than 2 hours, and this
include time it take to reboot servers.

I have bought a router on ebay for to help study with. I want to use web
browser for to configure this router, but I cannot seem to get it to come up.
I use the telnet program (From a Windows Server   to log into this router but
all there is a command line. It look almost like an old DOS program. I hope
Cisco does not still emulate DOS when Windows has been around many years. This
could a big mistake for them.

If anyone need help on setting routers, let me know. I will be willing to
help. Also, it seems Cisco allow test taker to look at website during CCIE
exam. In the MCSE program there is no help available. You must not look at any
material while taking exam. I think it should be fun to have a book open
exam.

Do you think I should get a Voice CCIE, or a Security CCIE for the second CCIE
I get. I am not familiar with the differences between them? I did recently set
up Security for Microsoft Vista, so maybe Security should be the way to go.

Also I want to say to Darby. You seem like a nice man (i hope you are man, not
woman. if so i apologize). You should try for to relax a little more and take
care of your health. If you can't get CCIE this week, you will be able to get
it next week. I know sometimes you get in a hurry, but your health is more
important than passing exam this week. Just make up study on the weekend and
take exam the following week. You should trust yourself more and not spend so
much money on instructions. Do you have relationship with your instructor? You
seem very close.

One more question. What does HTH mean?

HTH,

Hiriam

• To configure the EIGRP default route, use the following global configuration command:

ip default-network network-number

• The network-number will be announced to other routers as the last-resort gateway.
• In order for the router – where this command is configured – can consider the network as a candidate default route, the network must be reachable by this router.
• In addition, the network number 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 their gateway of last resort to this default network. This could be:
  • An EIGRP-derived network in the routing table.
  • Generated with a static route and redistributed into EIGRP.

The following scenario is based on the example given in page 96 of the BSCI study guide.

Dynampis .net Config file:

# EIGRP ip-default network Command - page 96 Of BSCI study guide
autostart = False
ghostios = true
sparsemem = true

[localhost]

    [[7200]]
        image = C7200.BIN
        # On Linux / Unix use forward slashes:
        # image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
        npe = npe-400
        ram = 160

    [[ROUTER A]]
        fa0/0 = B fa0/0
        s1/0 = C s1/0
        model = 7200
        console = 2001
        idlepc = #this is a system-specific setting

    [[router B]]
        model = 7200
        console = 2002
        idlepc = #this is a system-specific setting    

    [[router C]]
        model = 7200
        console = 2003
        idlepc = #this a system-specific setting

Router A Configuration:

!
interface FastEthernet0/0
 ip address 10.5.1.1 255.255.255.0
 duplex auto
 speed auto
!
interface Serial1/0
 ip address 172.31.5.1 255.255.255.252
 serial restart-delay 0
!
!
router eigrp 1
 network 10.0.0.0
 network 172.31.0.0
 auto-summary
!
ip classless
ip default-network 172.31.0.0
!

• The command ip default-network 172.31.0.0 is configured on Router A to allow 172.31.0.0 network as a candidate default network.
• The command network 172.31.0.0 passes the network 172.31.0.0 to Router B, so that router B can use it as its default network and set its gateway of last resort to this network.

Router B configuration:

interface FastEthernet0/0
 ip address 10.5.1.3 255.255.255.0
 duplex auto
 speed auto
!
router eigrp 1
 network 10.5.1.3 0.0.0.0
 auto-summary
!
ip classless
!

Router C configuration:

!
interface Serial1/0
 ip address 172.31.5.2 255.255.255.252
 serial restart-delay 0
!
router eigrp 1
  network 172.31.0.0
 auto-summary
!
ip classless

Router B: IP routing table:

B# sh ip route

Gateway of last resort is 10.5.1.1 to network 172.31.0.0

D*   172.31.0.0/16 [90/2172416] via 10.5.1.1, 00:10:38, FastEthernet0/0
     10.0.0.0/24 is subnetted, 1 subnets
C       10.5.1.0 is directly connected, FastEthernet0/0

• The EIGRP-learned 172.31.0.0 network is marked as a candiate default network indicated by the * in the routing table.
• The gateway of last resort is also set to 10.5.1.1 (Router A) to reach the default network 172.31.0.0.

Router A: IP routing table

A(config)#do sh ip route

Gateway of last resort is 0.0.0.0 to network 172.31.0.0

 *   172.31.0.0/16 is variably subnetted, 2 subnets, 2 masks
D*      172.31.0.0/16 is a summary, 00:12:27, Null0
C       172.31.5.0/30 is directly connected, Serial1/0
     10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D       10.0.0.0/8 is a summary, 00:12:27, Null0
C       10.5.1.0/24 is directly connected, FastEthernet0/0

• In earlier versions of IOS, the router on which the ip default-network command was configured would not set the gateway of last resort.
• As highlighted above, it now sets the gateway of last resort to 0.0.0.0, to the network specified – 172.31.0.0.

• By default, RIPv2 and EIGRP perform automatic network summarization at classful boundaries, just like a classful protocol does.
  • The diffrence between these two protocols and their predecessors (RIPv1 and IGRP) is that you can turn off automatic summarization.
  • To turn off, use the router configuration command:

no auto-summary

• OSPF and IS-IS RIP and EIGRP perform automatic network summarization by default.

Example:

• The diagram above shows a RIPv2 network where autosummarization occurs.

Dynamips .net Configuration:

autostart = False
ghostios = true
sparsemem = true

[localhost]

    [[7200]]
        image = \Program Files\Dynamips\images\c7200-js-mz.124-3\C7200-JS.BIN
        # On Linux / Unix use forward slashes:
        # image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
        npe = npe-400
        ram = 160

    [[ROUTER A]]
        S1/0 = B s1/0
        model = 7200
        console = 2001
        idlepc = 0x6082d7a0

    [[router B]]
        s1/1 = C s1/0
        model = 7200
        console = 2002
        idlepc = 0x607016a0

    [[router C]]
        model = 7200
        console = 2003
        idlepc = 0x607016a0

Router A Config:

!
interface FastEthernet0/0
 ip address 172.16.2.1 255.255.255.0
 duplex half
 no keepalive
!
interface Serial1/0
 ip address 172.16.1.1 255.255.255.0
 serial restart-delay 0
!
router rip
 version 2
 network 172.16.0.0

Router B Config:

!
interface Serial1/0
 ip address 172.16.1.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 192.168.5.2 255.255.255.0
 serial restart-delay 0
!
router rip
 version 2
 network 172.16.0.0
 network 192.168.5.0
!

Router C Config:

!
interface Serial1/0
ip address 192.168.5.1 255.255.255.0
serial restart-delay 0
!
router rip
version 2
network 192.168.5.0
!

• In the RIPv2 network above, Router B performs a defualt behavior of automatically summarizing the 172.16.1.0/24 and 172.16.2.0/24 networks learned from B’s connected subnet and A’s advertised subnet.

C# sh ip route
Gateway of last resort is not set

R    172.16.0.0/16 [120/1] via 192.168.5.2, 00:00:05, Serial1/0
C    192.168.5.0/24 is directly connected, Serial1/0

• In Router C’s routing table, notice that it, indeed, learns of a summarized route from it’s neighbor 192.168.5.2, which is Router B.
• A simple no auto-summary command on Router B, changes the routing table on Router C.

B(config)#router rip
B(config-router)#no auto-summary

• Now looking at Router C’s IP routing table, we see:

C# sh ip route
Gateway of last resort is not set

     172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
R       172.16.0.0/16 [120/1] via 192.168.5.2, 00:00:29, Serial1/0
R       172.16.1.0/24 [120/1] via 192.168.5.2, 00:00:00, Serial1/0
R       172.16.2.0/24 [120/2] via 192.168.5.2, 00:00:00, Serial1/0
C    192.168.5.0/24 is directly connected, Serial1/0

• Notice now that both 172.16.1.0/24 and 172.16.2.0/24 networks are advertised with both prefix and subnet mask.

Classful Routing Protocol Concepts

• Classful routing protocols do not include subnet mask information in their routing updates.
• A router sends the entire subnet address when an update packet involves a subnet of the same classful network as the IP address of the transmitting interface.
• If sending an update about a subnet of a network across an interface belonging to a different network, the router will send the classful summary route. This is called autosummarization across the network boundary.

Example:

Dynagen configuration:

autostart = False
ghostios = true
sparsemem = true

[localhost]

[[7200]]
image = C7200.BIN
# On Linux / Unix use forward slashes:
# image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
npe = npe-400
ram = 160

[[ROUTER A]]
S1/0 = B s1/0
model = 7200
console = 2001
idlepc = 0x6082d7a0

[[router B]]
s1/1 = C s1/0
model = 7200
console = 2002
idlepc = 0x607016a0

[[router C]]
model = 7200
console = 2003
idlepc = 0x607016a0

Router A Config:

interface FastEthernet0/0
 ip address 10.1.0.1 255.255.0.0
 duplex half
 no keepalive
!
interface Serial1/0
 ip address 10.2.0.1 255.255.0.0
 serial restart-delay 0
!
router rip
 network 10.0.0.0
!
ip classless

Router B Config:

interface FastEthernet0/0
 no ip address
 shutdown
 duplex half
!
interface Serial1/0
 ip address 10.2.0.2 255.255.0.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 172.16.2.2 255.255.255.0
 serial restart-delay 0
!
router rip
 network 10.0.0.0
 network 172.16.0.0
!
ip classless

Router C Config:

interface FastEthernet0/0
 ip address 172.16.1.1 255.255.255.0
 duplex half
 no keepalive
!
interface Serial1/0
 ip address 172.16.2.1 255.255.255.0
 serial restart-delay 0
!
router rip
 network 172.16.0.0
!
ip classless

Router B: show ip route
Gateway of last resort is not set

     172.16.0.0/24 is subnetted, 2 subnets
R       172.16.1.0 [120/1] via 172.16.2.1, 00:00:20, Serial1/1
C       172.16.2.0 is directly connected, Serial1/1
     10.0.0.0/16 is subnetted, 2 subnets
C       10.2.0.0 is directly connected, Serial1/0
R       10.1.0.0 [120/1] via 10.2.0.1, 00:00:21, Serial1/0

• In the output above, Router A advertises the 10.1.0.0 subnet to router B because the interface connecting them belongs to the same major classful 10.0.0.0 network. When router B receives the update packet, it assumes that the 10.1.0.0 subnet uses the same 16-bit mask as the one used on its 10.2.0.0 subnet.
• Similarly, Router C advertises the 172.16.1.0 subnet to router B because the interface connecting them belongs to the same major classful 172.16.0.0 network. Therefore, router B’s routing table has information about all the subnets that are in use in the network.

Router A: show ip route
Gateway of last resort is not set

R    172.16.0.0/16 [120/1] via 10.2.0.2, 00:00:16, Serial1/0
     10.0.0.0/16 is subnetted, 2 subnets
C       10.2.0.0 is directly connected, Serial1/0
C       10.1.0.0 is directly connected, FastEthernet0/0

• In the output above however, router B summarizes the 172.16.1.0 and 172.16.2.0 subnets to 172.16.0.0 before sending them to router A. Therefore, router A’s routing table contains summary information about only the 172.16.0.0 network.

Router C: show ip route
Gateway of last resort is not set

172.16.0.0/24 is subnetted, 2 subnets
C       172.16.1.0 is directly connected, FastEthernet0/0
C       172.16.2.0 is directly connected, Serial1/0
R    10.0.0.0/8 [120/1] via 172.16.2.2, 00:00:02, Serial1/0 

• Similarly above, router B summarizes the 10.1.0.0 and 10.2.0.0 subnets to 10.0.0.0 before sending the routing information to router C. This summarization occurs because the update crosses a major network boundary. The update goes from a subnet of network 10.0.0.0, subnet 10.2.0.0, to a subnet of another major network, network 172.16.0.0. Router C’s routing table contains summary information about only the 10.0.0.0 network.

On Demand Routing (ODR)

• Applicable in a hub-and-spoke topology only.
• Uses Cisco Discovery Protocol (CDP)
  • Sent as multicast
  • Sent every 60 seconds by default
    • cdp timer adjusts the timer.
  • Enabled by default.
  • Except ATM where CDP must be explicitly enabled.
• Configured on hub router
  • router odr global configuration command.
• Stub router can’t have an IP routing protocol. In fact, no IP routing protocol is considered a stub by ODR.
• WAN links such as dialer links and Frame Relay, use broadcast keyword in mapping statements.

Example:

autostart = False
ghostios = true
sparsemem = true

[localhost]

    [[7200]]
        image = C7200.BIN
        # On Linux / Unix use forward slashes:
        # image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image
        npe = npe-400
        ram = 160

    [[ROUTER A]]
        S1/0 = B s1/0
        model = 7200
        console = 2001
        idlepc = 0x6082d7a0

    [[router B]]
        s1/1 = C s1/0
        s1/2 = D s1/0
        model = 7200
        console = 2002
        idlepc = 0x607016a0

    [[router C]]
        model = 7200
        console = 2003
        idlepc = 0x607016a0

    [[router D]]
        model = 7200
        console = 2004
        idlepc = 0x607016a0

Here’s the configs:

Router B (Hub Router):

interface Loopback0
 ip address 10.4.1.1 255.255.255.255
!
interface Serial1/0
 ip address 10.1.1.1 255.255.255.252
 serial restart-delay 0
!
interface Serial1/1
 ip address 10.2.2.1 255.255.255.252
 serial restart-delay 0
!
interface Serial1/2
 ip address 10.3.3.1 255.255.255.252
 serial restart-delay 0

Router A:

interface Loopback0
 ip address 172.16.1.1 255.255.255.0
!
interface Serial1/0
 ip address 10.1.1.2 255.255.255.252
 serial restart-delay 0

Router C:

interface Loopback0
 ip address 172.16.2.1 255.255.255.0
!
interface Serial1/0
 ip address 10.2.2.2 255.255.255.252
 serial restart-delay 0
!

Router D:

interface Loopback0
 ip address 172.16.3.1 255.255.255.0
!
interface Serial1/0
 ip address 10.3.3.2 255.255.255.252
 serial restart-delay 0
!

• As soon as ODR is configured and running, routes from the stub routers are identified in the hub router’s routing table with an o character (shown below)
• Notice in the example that the metric is 1, and the administrative distance for ODR is 160.
• Also, do not confuse the o character of ODR routes with the O character of OSPF routes.

B#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

     172.16.0.0/24 is subnetted, 3 subnets
o       172.16.1.0 [160/1] via 10.1.1.2, 00:00:56, Serial1/0
o       172.16.2.0 [160/1] via 10.2.2.2, 00:00:54, Serial1/1
o       172.16.3.0 [160/1] via 10.3.3.2, 00:00:55, Serial1/2
     10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
C       10.3.3.0/30 is directly connected, Serial1/2
C       10.2.2.0/30 is directly connected, Serial1/1
C       10.1.1.0/30 is directly connected, Serial1/0
C       10.4.1.1/32 is directly connected, Loopback0

I have just started going back at the beginning of the BSCI study guide to start the exam preparation. I plan on taking the exam by mid-March and hoping that I can get myself ready by then. I’ve been trying to find ways to stimulate my learning and help my memory retention for details that can only be done by rote memorization. I think I’ve pretty much improved my understanding of the concepts. It’s the minute details that I struggle with; for example, remembering the admin distance of all the routing protocols, or remembering all the OSPF LSA types. Hmmm… come to think of it, I do remember LSA types better than I thought after I wrote the last sentence .

After reading Greg Ferro’s tips on study methods yesterday, I was motivated to follow some of his suggestions. Last night I spent a good two and a half hours of solid studying – no TVs, no music, no IMs, no Internet (except when I had to look up things on the Doc pages). It worked for that time. Hopefully I can keep up this type of intensity for the next month.   In fact, in addition to the no-ADD-inducing-activites he mentioned, I even used a stopwatch to time my study sessions. I’ve done it before and even wrote about it in my previous posts. The challenge is to consistently improve on those study skills. I’m also considering picking up one of the iPod flahscard apps, similar to the one he mentioned on his post.

For the remaining of this week, I plan to get through the static routing and RIP portion of the materials and hopefully get started on EIGRP on the weekend. I’ve already finished my third time reading throught chapter 2 (with notes). I’ll hopefully be able to get through a couple of nights of labbing – or maybe one, since I have the impression that this part is not covered as deeply on the exam compared to the other protocols. I may also decide to create a high-level overview of my study schedule that I can follow – and also post on my BSCI study schedule page, which I regretfully neglected. Why? It turns my BSCI study schedule page is the most visited page on my site – 300 hits on that one page for the last 2 months. And regretfully it has been my most negelected. I’ve actually received many emails (ok, just two) asking me to update it. Sorry guys if I was such a disappointment.

Anyway, anybody have experience with Boson test engines vs Transcender for CCNP? I’m considering getting one of those.