Thus spake Mike Wronski
|Thus spake Mike Andrews |>The real problem is that the ARC is letting less specific routes override |>more specific routes, and thus confusing itself about its own netmask. |>That's apparently why communication fails with the new DR:
|Hrmm...ok...so its sending the wrong netmask...the netmask in the |routing table in the Hello packets....
|So...that means that someone isn't paying attention to the Hello packets |in the normal course of operation. Theoretically, sending a Hello |packet with the wrong netmask (as the Arc is doing) should destroy the
HARC is not sending anything wrong in this case. It is doing something wrong based on information it receives from the DR.
Semantics. :)
The card should not be changing its netmask for any reason. But it obviosly is doing this when it receives a less specific route from the DR.
OK, the Arc is getting a less-specific route, accepting it and installing it in the routing table instead of a more-specific one...a no-no to begin with...then using that information in its Hello information. I guess its a matter of how its coded as to what the root cause of the problem really is, but ultimately, the netmask value in the Hello packets don't match what was configured on the interface...end result, boo boo by the Arc. :)
|I believe administrative distance is a Cisco proprietary thing and is |not transmitted via OSPF. The Arc's don't seem to have nearly the |control over route redistribution and such that the Cisco's do. :/
Actually its not a Cisco thing. Its called Internal Distance in the RFC. This information is used for tie breaking when equal cost routes are present and the admin does have a preference.
Uhm, no. Administrative distance is used in Cisco's to determine which route to use when multiple routes are present in different routing protocols. ie, connected routes have a lower admin distance (are preferred) than statics, which are lower than eBGP, which is lower than OSPF, which is lower than RIP, which is lower than iBGP. There are others in there of course (IS-IS, Hello, EGP, etc.), but those are the main ones. When you're putting in a static route, you can set it at a specific administrative distance (ie, Mike was sticking them in at 250) which means that the same route picked up by OSPF will be preferred over the static one, when, by default, a static route will be used rather than the OSPF. Much the same type of thing can be done with routing protocols...for example, I have two cisco's redistributing routes from RIP into OSPF on one network...this causes problems based on the administrative distance...the solution was to tell one router to deal with OSPF at a higher administrative distance than RIP (so it preferred the RIP routes over OSPF). This prevented a nice loop in the routing updates. :) This information is not transmitted in OSPF in any way. -- Jeff McAdams Email: jeffm@iglou.com Head Network Administrator Voice: (502) 966-3848 IgLou Internet Services (800) 436-4456 - To unsubscribe to usr-tc, send an email to "majordomo@xmission.com" with "unsubscribe usr-tc" in the body of the message. For information on digests or retrieving files and old messages send "help" to the same address. Do not use quotes in your message.