Re: route-map and as-path confusion

Thanks for the regexp (_3_.*5$)

I am wondering what cisco folks were smoking when they wrote the code ? I am
tempted to go back to what I was doing in me previous life: Unix. At least
"if...then...else" does not turn magically into "if...then...also"

On 23 November 2010 15:16, Bob Sinclair <bob_at_bobsinclair.net> wrote:

> Hi Jack,
>
> Note that when multiple lines reference the same type of filter (as-path
> acl
> here) IOS turns it into an "or"
>
> For example, I entered this:
>
> R4(config)#ip as-path access-list 200 permit _1771_
> R4(config)#ip as-path access-list 201 permit _1581$
> R4(config)#route-map PATH deny
> R4(config-route-map)#match as-path 200
> R4(config-route-map)#match as-path 201
> R4(config-route-map)#route-map PATH permit 20
> R4(config-route-map)#end
>
> But IOS rendered the route map as:
>
> !
> route-map PATH deny 10
> match as-path 200 201
> !
> route-map PATH permit 20
>
>
> To get the AND that you want you could try a single as-path statement that
> includes both conditions. In my case
>
> ip as-path access-list 200 permit _1771_.*1581$
>
> In your example something like: ip as-path access-list 35 _3_.*5$
>
> HTH,
>
>
> Bob Sinclair CCIE 10427 CCSI 30427
> CIERS2 Online Instructor
> www.bobsinclair.net
>
>
> > -----Original Message-----
> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> > Jack Router
> > Sent: Tuesday, November 23, 2010 1:53 PM
> > To: ccielab_at_groupstudy.com
> > Subject: route-map and as-path confusion
> >
> > Hello all,
> >
> > I have a problem with a route-map. Here is the scenario:
> >
> > R1(AS1)----R2(AS2)----R3(AS3)----R4(AS4)----R5(AS5)----R6(AS6)
> >
> > Routers advertise networks: R1: 1.0.0.0, R2: 2.0.0.0 etc...
> >
> > On R1 I want to filter routes that traversed AS3 *AND* originated in
> > AS5. I
> > want to use route-map to do this.
> >
> > Step 1. Define as-path access list:
> > # ip as-path access-list 3 permit _3_
> > # ip as-path access-list 5 permit _5$
> >
> > Step 2. Match as-path in route map. This route map is meant to match
> > both
> > as-path access lists:
> > # route-map TST deny 10
> > # match as-path 3
> > # match as-path 5
> > # route-map TST permit 99
> >
> > Step 3. Apply route-map to neighbor in AS2:
> > # router bgp 1
> > # neighbor 10.1.12.2 route-map TST in
> >
> > At this point I should see on R1 all prefixs with xception of 5.0.0.0
> >
> > "sh ip bgp" shows now:
> >
> > *> 1.0.0.0 0.0.0.0 0 32768 i
> > *> 2.0.0.0 10.1.12.2 0 0 2 i
> >
> > It looks that only as-path 3 was applied. Why ?
> > My understanding is that if multiple match statement are present within
> > single route-map instance, thy ALL must match. In this case only
> > 5.0.0.0
> > matches both access-lists and only 5.0.0.0 should be removed from R1.
> >
> >
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Received on Tue Nov 23 2010 - 16:04:47 ART