From: 1cmpecho (1cmpecho@hotpop.com)
Date: Fri Dec 26 2003 - 15:30:13 GMT-3
i labbed a similar situation up and i was able to duplicate some of this...
the stub router (even though it didn't advertise it as a summary to the
distribution router) created a summary locally and pumped it to null
0. only after disabling auto summary on the stub was i able to have
class"like/full" discontigious subnets.
in my example:
stub router had several variations of 20.x.x.x (/24, /30, etc.)
-it created subnet entries for these and advertised them to the
distro router
-it also created a /8 to null0 but did not advertise this to the
distro router
this is fine - until we place a 20.x.x.x /whatever on the other side of the
distro router....then the stub router can handle icmp connectivity to more
specific locally connected subnets, but (if no default exists - which in
real life - it likely would) for that subnet on the other side of the
distro router, it's not going to be able to resolve it.
disabling auto-summary under the eigrp process on the stub router will fix
this. if the auto summary is still enabled on the distro router, it will
send 20.0.0.0 /8 to the stub router and this will effectively replace the
20.0.0.0 /8 > null0 that had been in the stub router.
the 'eigrp stub static connected' nor 'eigrp stub static connected summary'
did NOT send that summary to the distro router in my situation....the
distro router learned the various subnets attached to the stub router with
the appropriate masks....and hence created a /8 that was then visible to
the stub (via the distro router).
At 05:47 PM 12/26/2003 +0530, Pankaj Madhukar Kulkarni wrote:
>Hi Group,
>
>I was trying out a few scenarios related to EIGRP stub routing. I am
>refering to the below document from the Cisco site.
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120
>limit/120s/120s15/eigrpstb.htm
>
>The document states that:
>
>In the following example, the eigrp stub command is issued with the
>connected and static keywords to configure the router as a stub that
>advertises connected and static routes (sending summary routes will not be
>permitted):
>router eigrp 1
>network 10.0.0.0
>eigrp stub connected static
>auto-summary (implicit)
>
>I replicated the scenario but observed that summary route for local network
>is advertised to the neighbors. Also, if I issue the "summary" option but
>disable "auto-summary" within the EIGRP process, the subnet is advertised.
>
>Now, what is the significance of "summary" option? I have similar
>conflicting observation with the "connected" option as well.
>
>Would appreciate some help in this matter and hope this doesn't turn out to
>be a bug in the IOS.
>
>Regards,
>Pankaj K
>
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