Re: EIGRP distribute-lists with route-maps

I missed the detail on the e0/0 interface.

Offset-list <ACL> in

With regard to PBR, I think it's semantics, really. You are using a policy
to effectively manipulate a route, regardless of when your policy is used.
 And if you're willing to take that chance in the Lab, by all means do so.
 I didn't. You may be right. It's just not a risk I was willing to take.
;)

Tim

On Sat, Jul 26, 2014 at 10:46 AM, Billy Singh <billysingh_at_ipanyany.com>
wrote:

> Bandwidth and delay. R4 is connecting to both upstream routers via the
> same outgoing interface, i.e. e0/0, so I'm not following...
>
> I disagree with the simple view that any time you use a route-map you're
> doing PBR. Route-maps may be a functional component of PBR, but by
> themselves I don't imagine they'd constitute PBR. The routing is still
> being done by R4 using the RIB. PBR would be if packets were routed before
> the RIB was consulted, no? If I'm manipulating the routes before they enter
> the EIGRP topology table, therefore changing how they enter the RIB that's
> not PBR.
>
>
> On 07/27/14 00:27, Tim Cribbs Jr. wrote:
>
> Ask yourself what does EIGRP use (the defaults) to decide the best route.
> 2 metrics should come to mind. Using route-maps is PBR, which is
> prohibited. The answer is easier than you think.
>
>
> On Sat, Jul 26, 2014 at 10:18 AM, Billy Singh <billysingh_at_ipanyany.com>
> wrote:
>
>> Good evening all,
>>
>> I was doing some practise labs tonight and playing around with EIGRP.
>> I'm trying to grasp a better understanding of the limits of route-maps
>> when used with distribute-lists in EIGRP.
>>
>> For the sake of simplicity, let's imagine a topology with three routers
>> all connected over a shared, broadcast media (Ethernet).
>>
>> R2 & R3 are the upstream routers both advertising a network 200.2.2.0/24
>>
>> R4 is the downstream router with EIGRP neighbour adjacencies to both
>> these upstream routers. As a result, R4 is doing equal cost
>> load-balancing between both upstream routers for 200.2.2.0/24.
>>
>> sh ip ro | s 200.2.2.0
>> D 200.2.2.0/24 [90/1024640] via 10.1.1.3, 00:00:16, Ethernet0/0
>> [90/1024640] via 10.1.1.2, 00:00:16, Ethernet0/0
>>
>> The requirement was to have R4 prefer the route via R2, unless R2 was
>> unavailable, in which case it would route through R3.
>>
>> - Configuration can only be done on R4.
>> - No PBR (Policy Based Routing).
>> - No manipulation of the Administrative Distance (AD) allowed (This was
>> actually the easy answer, but I wanted to try and find an alternate
>> method).
>>
>> So we can use route-maps in conjunction with distribute lists and I
>> guess this is where my confusion currently is. Here's what I tried to do:
>>
>> 1. Access list to match the route:
>>
>> access-l 44 permit 200.2.2.0 0.0.0.255
>>
>> 2. Access list to match one of the route-sources (R3):
>>
>> access-l 3 permit host 10.1.1.3
>>
>> 3. Route-map configuration. I'm trying to bump up the metric of a route
>> by 1000 so it's no longer the preferred route:
>>
>> route-map PREFER-R2 permit 10
>> match ip addr 44
>> match ip route-source 3
>> set metric +1000
>> route-map PREFER-R2 permit 20
>>
>> 4. Apply it to the EIGRP routing instance:
>>
>> router eigrp AS100
>> addr ipv4 uni auto 100
>> topo base
>> distrib route-map PREFER-R2 in
>>
>>
>> And it didn't end up working. So clearly my intended use of the
>> route-map in the above scenario is invalid. Probably fine for when
>> redistributing, but not when used in conjunction with distribute lists.
>> If I add a different "set" parameter (one which seems to be commonly
>> referred to in the configuration guide; a route tag), then I see that it
>> gets applied:
>>
>>
>> sh ip ro 200.2.2.0
>> Routing entry for 200.2.2.0/24
>> Known via "eigrp 100", distance 90, metric 1024640
>> Tag 200, type internal
>> Redistributing via eigrp 100
>> Last update from 10.1.1.3 on Ethernet0/0, 00:00:13 ago
>> Routing Descriptor Blocks:
>> * 10.1.1.3, from 10.1.1.3, 00:00:13 ago, via Ethernet0/0
>> Route metric is 1024640, traffic share count is 1
>> Total delay is 1002 microseconds, minimum bandwidth is 10000 Kbit
>> Reliability 255/255, minimum MTU 1500 bytes
>> Loading 1/255, Hops 1
>> Route tag 200
>> 10.1.1.2, from 10.1.1.2, 00:00:13 ago, via Ethernet0/0
>> Route metric is 1024640, traffic share count is 1
>> Total delay is 1002 microseconds, minimum bandwidth is 10000 Kbit
>> Reliability 255/255, minimum MTU 1500 bytes
>> Loading 1/255, Hops 1
>>
>> I'm looking through the configuration guide and the CLI reference to try
>> and work out what match criteria and set commands are available when
>> route-maps are used under different contexts, but I'm not having much
>> luck finding anything thorough or concrete. When you think about it, it
>> does kind of make sense, distribute-lists are for filtering not routing
>> metric manipulation but since route-maps allow for so much manipulation
>> of routes an understanding of what parameters you can use under what
>> scenarios would be great.
>>
>> Ideas or resources?
>>
>> Thanks.
>>
>> Billy
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Sat Jul 26 2014 - 11:07:22 ART