I'm currently studying/practicing for my CCNA exam and setup a lab of sorts to do some hands on training. To emulate a wan/telco connection between the two routers I used the following article published by Cisco to create a direct router-router connection:
http://www.cisco.com/warp/
The routers being used are two Cisco 2500 series - connected via Aux ports (using the async1 interface as defined in the above http link). Here is a generic layout (hope it saves ok!):
Domain Server Exchange Server Host A
192.168.5.2/24 192.168.5.3/24 192.168.20.2/24
| | | | | | | | | ------|Switch 1|-------- |Switch 2|
| | | |
| | | E0 - 192.168.5.1/24 E0 - 192.168.20.1/24 |
------------------------{R
Aux - 192.168.10.2/24 Aux - 192.168.10.1/24
The switches are Cisco 3500 XL's. Domain Server is Win2K Server, Exchange Server is NT 4.0 and Host A is Win2K Pro.
If I create static routes for both routers, everything works fine. My problem is, I cannot get RIP or IGRP to work. I tried this by removing the static routes on both routers, then using the following commands on each router:
Config T
Router Rip
Network 192.168.0.0
Made sure they were set to no ip classless and that didn't work. To ensure they could both update via either RIP version (to eliminate a version issue) I then specified for the async1 interface (on both routers):
ip rip send version 1 2
ip rip receive version 1 2
and that didn't help either. Still no updates to either routing table.
Removed RIP and setup IGRP as follows:
router igrp 10
network 192.168.0.0
on both routers and that didn't work either. My suspicion is the link via the Aux ports is somehow interfering with RIP/IGRP communication but I have no clue how or what to do to correct it (if that's even possible). The article above has you set the "async dynamic routing" command which if I understand correctly should allow routing protocols over the link - but it still isn't working. I'd like to clear up this issue so I can pratice setting up routing protcols in the lab via the established link. Any help would be most appreciated!
This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.
Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.
If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.
Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.
Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.
Access the answers to your technology questions today.
30-day free trial. Register in 60 seconds.
Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.
Try it out and discover for yourself.
30-day free trial. Register in 60 seconds.
Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.
You may need to use the keyword "Broadcast" when configuring your link.
Many / most / all Serial connections default to not broadcasting across the link - RIP 1 needs broadcast, RIPII, OSPF, and BGP need multicasts (interpreted as a broadcast, generally speaking, by the router).
Check the syntax for you parameters, try using the "broadcast" keyword ....
Good Luck
Scott
SMack - I'm not familiar with out to enable broadcasting on that link, can you explain what needs to be done (i.e. the appropriate commands) or point me somewhere that would explain a little more please?
mikecr - No I haven't created an access list nor used the distribule-list command. Haven't quite made it that far in my studies ;) Could you elaborate please?
Just thinking outloud - but isn't ARP broadcast? And if those routers worked fine with static routes (pings could sucessfully travel from one network to the other - again, using static routes), doesn't that tell us broadcast is working over the aux-aux link? Also, thought it might help to see my config in case anyone else wants to jump in here:
Current configuration:
!
version 11.2
service password-encryption
service udp-small-servers
service tcp-small-servers
!
hostname Router_1
!
enable secret 5 $1$z3e0$8UKJg91Xh.Efjn8m53
enable password 7 025701411B114E
!
interface Ethernet0
description Practice Router 1
ip address 192.168.5.1 255.255.255.0
!
interface Serial0
no ip address
shutdown
!
interface Serial1
no ip address
shutdown
!
interface Async1
ip address 192.168.10.2 255.255.255.0
encapsulation ppp
async dynamic routing
async mode dedicated
!
router rip
network 192.168.0.0
!
no ip classless
!
line con 0
exec-timeout 0 0
password 7 05190F1B2244470C
login
line aux 0
modem InOut
transport input all
speed 38400
flowcontrol hardware
line vty 0 4
password 7 1315161B07
login
!
end
It think that it might be easier to finish going through your studies so you have a grasp of what we are talking about here before attempting any of this. Once you have finished. you can go back to the parts which you may not quite understand.
The "distribute-list" command is used to tell EIGRP what networks it will accept updates from and send updates to. This keeps your router from seeing networks that it doesn't need to know about. The access list is used to dictate from what networks your router will accept updates.
Example:
router eigrp 1
network 10.3.0.0
distribute-list 1 in
distribute-list 1 out
access-list 1 permit 10.0.0.0
lrmoore: Thank you for the update on RIP (it not understanding subnets). I did as you asked and set:
Router_1
Router RIP
Network 192.168.10.0 (Serial Interface)
Network 192.168.5.0 (LAN Interface)
and -
Router_2
Router RIP
Network 192.168.10.0 (Serial Interface)
Network 192.168.20.0 (LAN Interface)
I checked each router by using "sh ip route" expecting router_1 to learn about the 192.168.20.0 network via RIP and only connected interfaces show up (no entries labeled "R", only "C" entries). Same thing on router_2. So unless I did that wrong or have missed something I'm still not getting RIP to work. I also tried the EIGRP commands you provided (on both routers) with no effect.
mikecr: Thank you for taking the time to explain that for me. I do understand (at least at a very basic level) what distance vector and link state routing protocols are and how they function - though I admit I'm not entirely familiar with all the associated commands and what they do. However, given my situation and what I've presented so far I see no reason RIP shouldn't work and therein lies my problem. Your recommendation to use EIGRP with a distribute-list and access list goes outside of the scope of my question (how to get RIP to work over an Aux-Aux connection, not EIGRP) as that does not resolve my RIP problem - even if EIGRP did work. I'm at least fairly familiar with RIP and how it works and I feel that I am at least educated enough to discuss it with the others here in-so-far as my problem is concerned. Distribute/access list's aside - don't all routers running EIGRP within the same Autonomous System share routing information by default? Distribution-list and Access-List's are filters (to control the advertising and processing of routes - typically in a large [many router] environment). When working with just 2 routers - why would it be necessary to establish a distribution and access list? Perhaps I'm misunderstanding something, but I'm not sure I see the need for it.
I *think* the problem here is updates are not even making it across the aux-aux link and if that is true - no routing protocol is going to function (as we have seen so far). Is there any way to tell (once a routing protocol has been activated) that the updates are being sent and on the receiving side, being recieved? Perhaps that would be the first place I should start troubleshooting?
Try changing this:
>async dynamic routing
To this:
async default routing
Enables the router to pass routing updates to other routers over the AUX port configured as an asynchronous interface.
http://www.cisco.com/unive
Check your MTU size too: RIP and other routing protocols don't allow fragmentation. If your MTU is small (bacause it's an Async connection), it may be too small to pass the RIP (and other) updates.
IGRP, EIGRP, and OSPF are also very parameter sensitive: the parms (update timers / keepalives, etc) must agree on both sides of the link.
Scott
lrmoore - you nailed it! The article you provided gave me exactly what I needed. THANK YOU! SMack and mikecr, I'd like to thank you guys to for taking the time to try and help me as well, it is truly appreciated. Here is the pertinent information in the article that resolved my problem -
I used the async dynamic routing command when what I needed was the async default routing command
async dynamic routing
To enable manually configured routing on an asynchronous interface, use the async dynamic routing command in interface configuration mode. To disable routing protocols, use the no form of this command; static routing is still used.
async default routing
To enable the router to pass routing updates to other routers over the AUX port configured as an asynchronous interface, use the async default routing command in interface configuration mode. To disable dynamic addressing, use the no form of this command.
lrmoore provided the information as referenced in this article:
http://www.cisco.com/unive
Business Accounts
Answer for Membership
by: LeepPosted on 2003-06-11 at 08:39:58ID: 8700729
Bummer - the pic didn't come through. Domain Server and Exchange Server connect to switch 1, switch 1 connects to router 1, router 1 to router 2, router 2 to switch to and Host A connects to Switch 2.
Router 1:
E0 - 192.168.5.1/24
Aux - 192.168.10.2/24
Router 2:
E0 - 192.168.20.1/24
Aux - 192.168.10.1/24
Domain Server:
192.168.5.2/24
Exchange Server:
192.168.5.3/24
Host A:
192.168.20.2/24
I apologize for any confusion.