From: Ken.Farrington@barclayscapital.com
Date: Mon Sep 29 2003 - 05:35:21 GMT-3
That's is brilliant!
Very very clear indeed.
Will be filing this e-m away :))
Many thx
-----Original Message-----
From: William Lijewski [mailto:ccie8642@hotmail.com]
Sent: 29 September 2003 08:13
To: Ken.Farrington@barclayscapital.com; arahman@cisco.com
Cc: ccielab@groupstudy.com
Subject: RE: Re-4: Route-Map Logic (Example from networkers 2000)
Lets walk through a couple of the routes:
*>130.10.10.0/24 150.50.5.68 111 0 100 50 i
The route map gets this route in and runs it through the first route-map
sequence, 10. Sequence 10 is going to permit any routes that have passed
through AS 50 and change their metric to 111. The 130.10.10.0/24 network
has passed through AS 50 so it gets its metric changed to 111 and the
route-map is exited since the network already matched a sequence. It
doesn't carry on to any other sequence numbers.
*> 140.10.10.0/24 150.50.5.68 0 222 0 100 75 i
This network gets run through Sequence 10 of the route-map. It hasn't gone
through AS 50 so its metric isn't set to 111. It didn't match Sequence 10
so it is sent on to Sequence 20 to see if it matches there. Sequence 20
checks to see if the network has passed through AS 75, which it has. So it
sets its local preference to 222 and exits the route-map.
*> 160.20.20.0/24 150.50.5.68 111 0 100 50 75 i
This network is checked in Sequence 10 to see if it has passed through AS
50, which it has. Since it passed through AS 50 its metric is set to 111.
Since the network matched Sequence 10, the route-map is done with this
network and it is not checked against the rest of the Sequence numbers. So
only the metric is changed, not the local preference since it never get to
Sequence 20 (because it already matched Sequence 10).
Something else to remember is that a route-map has an implicit deny at the
end of it just like an access-list. So if a network came in that didn't
match Sequence 10 and have its metric changed to 111, and it didn't match
Sequence 20 and have its local preference changed to 222, it would be
dropped since it didn't match any of the Sequences. You could put a blank
route-map statement to let in all other networks that didn't pass through AS
50 or 75.
route-map assign permit 30
If you don't specify any match criteria on the route-map it will match
everything.
Hope that helps you out some,
Bill Lijewski
CCIE #8642
Network Learning Inc
5 Day R&S CCIE Bootcamp Instructor
>From: Ken.Farrington@barclayscapital.com
>Reply-To: Ken.Farrington@barclayscapital.com
>To: arahman@cisco.com
>CC: ccielab@groupstudy.com
>Subject: RE: Re-4: Route-Map Logic (Example from networkers 2000)
>Date: Mon, 29 Sep 2003 07:28:27 +0100
>
>It looks like here it has gone on to the second route-map statement or
>am I missing something fundamental
>
>-----Original Message-----
>From: Arifur Rahman [mailto:arahman@cisco.com]
>Sent: 29 September 2003 05:02
>To: Ken.Farrington@barclayscapital.com
>Cc: jhays@jtan.com; info@mpauli.de; Ken.Farrington@barclayscapital.com;
>ccielab@groupstudy.com
>Subject: RE: Re-4: Route-Map Logic (Example from networkers 2000)
>
>
>Hi
>I see expected result. If it match first route-map it did not go to 2nd
>route map statement.
>
>router bgp 200
> neighbor 150.50.5.68 remote-as 100
> neighbor 150.50.5.68 route-map assign in
>!
>ip as-path access-list 1 permit _50_
>ip as-path access-list 2 permit _75_
>!
>route-map assign permit 10
> match as-path 1
> set metric 111
>!
>route-map assign permit 20
> match as-path 2
> set local-preference 222
>
> Network Next Hop Metric LocPrf Weight Path
>*> 130.10.10.0/24 150.50.5.68 111 0 100 50 i
>*> 130.20.20.0/24 150.50.5.68 111 0 100 50 i
>*> 140.10.10.0/24 150.50.5.68 0 222 0 100 75 i
>*> 140.20.20.0/24 150.50.5.68 0 222 0 100 75 i
>*> 160.10.10.0/24 150.50.5.68 111 0 100 50 75 i
>*> 160.20.20.0/24 150.50.5.68 111 0 100 50 75 i
>
>
>At 07:15 PM 9/28/2003 +0100, Ken.Farrington@barclayscapital.com wrote:
> >Hi Guys,
> >
> >I am getting a little more confuse now and I hope this e-mail makes
> >sense to all, im off for a cigerette and when I come back, this
> >e-mail probably wont make sense to me :))
> >
> >
> >
> >if I have
> >
> >ip as-path access-list 2 permit ^$
> >!
> >route-map test permit 10
> > match as-path 2
> > set metric 333
> >!
> >route-map test permit 20
> > match as-path 2
> > set metric 444
> >!
> >
> >It sets the metric on the neighboring BGP router to 333 only for
> >prefixes that match the as-path criteria. It does not go onto the
> >next stage of the route map or if it does, it does not set the
> >metric. This is inline which what the networkers thing says.
> >
> >
> >Now if I have this
> >
> >ip as-path access-list 2 permit ^$
> >ip as-path access-list 3 permit ^300
> >!
> >route-map test permit 10
> > match as-path 2
> > set metric 333
> >!
> >route-map test permit 20
> > match as-path 3
> > set metric 444
> >!
> >
> >It sets the metric to 333 on wotever matches criteria in as-path list
> >2 and then goes on to set the metric to 444 for any criteria that
> >meets as-path list 3.
> >
> >So can I assume, a prefix can only be matched once in a bgp table (or
> >routing table) and then exits or goes on the the next line of the
> >route-map? Which then the particular prefix that has already been
> >matched against once cannot be matched against again?
> >
> >Also, if it does go on to the next stage of the route-map, how does
> >it know not to match again against a ;prefix that has already been
> >matched?
> >
> >Concept I cant get to grasps with here?
> >
> >Many thx
> >
> >Confused Kennyboy
> >
> >-----Original Message-----
> >From: Jonathan V Hays [mailto:jhays@jtan.com]
> >Sent: 28 September 2003 15:49
> >To: info@mpauli.de; Ken.Farrington@barclayscapital.com
> >Cc: ccielab@groupstudy.com
> >Subject: RE: Re-4: Route-Map Logic (Example from networkers 2000)
> >
> >
> >I was a bit surprised at the results, but I am glad for the knowledge
> >gained.
> >
> >Thanks! Good information to know.
> >
> >Jonathan
> >
> >-----Original Message-----
> >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> >Of info@mpauli.de
> >Sent: Sunday, September 28, 2003 10:20 AM
> >To: jhays@jtan.com; Ken.Farrington@barclayscapital.com
> >Cc: ccielab@groupstudy.com
> >Subject: Re-4: Route-Map Logic (Example from networkers 2000)
> >
> >
> >Hi Jonathan,
> >
> >you're right concerning the def. weight. But if the default is in
> >effect, it is not displayed with sh ip bgp. The point was, to
> >demonstrate, that after a permit in a route-map, it is checked
> >against the other entrys. (Your point 2).
> >
> >Anyway, I've just changed the route-map:
> >
> >R2#sh ip bgp
> >BGP table version is 20, local router ID is 133.1.2.2
> >Status codes: s suppressed, d damped, h history, * valid, > best, i -
> >internal Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric LocPrf Weight Path
> >*>i1.1.1.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i2.2.2.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i3.3.3.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i4.4.4.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i5.5.5.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i6.6.6.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i10.10.1.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i133.1.253.0/24 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i144.10.13.0/24 133.1.3.3 444 100 0 5001 i
> >* i144.10.31.0/24 133.1.3.3 444 100 0 5001 i
> > Network Next Hop Metric LocPrf Weight Path
> >* i144.10.35.0/24 133.1.3.3 444 100 0 5001 i
> >*>i144.10.111.0/24 133.1.3.3 444 100 0 5001 i
> >*>i150.100.1.0/24 133.1.3.3 444 100 0 5001 i
> >*>i192.168.161.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i192.168.167.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i192.168.170.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i197.65.7.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i198.199.199.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i199.199.198.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i199.199.199.0 133.1.3.3 300 100 0 5001 65001
> >253 99 100 i
> >*>i201.201.201.0 133.1.3.3 444 100 0 5001 i
> >
> >Q.E.D. ;-)
> >
> >Cheers
> >Marcus
> >
> >
> >-------- Original Message --------
> >Subject: RE: Re-2: Route-Map Logic (Example from networkers 2000)
> >(28-Sep-2003 16:12)
> >From: jhays@jtan.com
> >To: info@mpauli.de
> >
> > > I see some flaws in this test.
> > >
> > > 1. You are setting local preference to the default, which is 100.
> > > So
> >it
> > > is not easy to tell if the route-map has actually done anything.
> > > You would do better to use a non-default value, such as 111.
> > >
> > > 2. Please note that each route is filtered by the route-map
> > > individually. If there are 10 routes, then the route-map is
> > > executed
> >10
> > > times. So one route might match on permit 10 while the next route
> > > matches on permit 20.
> > >
> > > To verify that the route-map is exiting on the first match for a
> > > given route, a better test might be this:
> > >
> > > route-map bla01 permit 10
> > > match as-path 10
> > > set metric 300
> > > !
> > > route-map bla01 permit 20
> > > match as-path 10
> > > set metric 444
> > >
> > > If the route-map does NOT exit after permit 10 has set the metric
> > > to 300, then the final metric will be 444.
> > >
> > > HTH,
> > >
> > > Jonathan
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> > > Behalf
> >Of
> > > info@mpauli.de
> > > Sent: Sunday, September 28, 2003 8:40 AM
> > > To: Ken.Farrington@barclayscapital.com
> > > Cc: ccielab@groupstudy.com
> > > Subject: Re-2: Route-Map Logic (Example from networkers 2000)
> > >
> > >
> > > Hi Ken,
> > >
> > > I've just tested it myself:
> > > Originating router:
> > >
> > > router bgp 1
> > > bgp router-id 133.1.5.5
> > > bgp log-neighbor-changes
> > > neighbor 133.1.2.2 remote-as 1
> > > neighbor 133.1.2.2 update-source Loopback0
> > > neighbor 133.1.2.2 route-reflector-client
> > > neighbor 133.1.2.2 route-map bla01 out
> > > neighbor 133.1.3.3 remote-as 5001
> > > neighbor 133.1.3.3 ebgp-multihop 2
> > > neighbor 133.1.3.3 update-source Loopback0
> > > neighbor 133.1.6.6 remote-as 1
> > > neighbor 133.1.6.6 update-source Loopback0
> > > neighbor 133.1.6.6 route-reflector-client
> > > !
> > > ip as-path access-list 10 permit 99
> > > ip as-path access-list 20 permit ^5001
> > > !
> > > !
> > > route-map bla01 permit 10
> > > match as-path 10
> > > set metric 300
> > > !
> > > route-map bla01 permit 20
> > > match as-path 20
> > > set local-preference 100
> > >
> > > The outcome on the destination router looks like this:
> > >
> > > R2#sh ip bgp
> > > BGP table version is 21, local router ID is 133.1.2.2 Status
> > > codes: s suppressed, d damped, h history, * valid, > best, i -
> > > internal Origin codes: i - IGP, e - EGP, ? - incomplete
> > >
> > > Network Next Hop Metric LocPrf Weight Path
> > > *>i1.1.1.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i2.2.2.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i3.3.3.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i4.4.4.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i5.5.5.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i6.6.6.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i10.10.1.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i133.1.253.0/24 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i144.10.13.0/24 133.1.3.3 100 0 5001 i
> > > * i144.10.31.0/24 133.1.3.3 100 0 5001 i
> > > Network Next Hop Metric LocPrf Weight Path
> > > *>i144.10.35.0/24 133.1.3.3 100 0 5001 i
> > > *>i144.10.111.0/24 133.1.3.3 100 0 5001 i
> > > *>i150.100.1.0/24 133.1.3.3 100 0 5001 i
> > > *>i192.168.161.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i192.168.167.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i192.168.170.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i197.65.7.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i198.199.199.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i199.199.198.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i199.199.199.0 133.1.3.3 300 100 0 5001
> >65001
> > > 253 99 100 i
> > > *>i201.201.201.0 133.1.3.3 100 0 5001 i
> > >
> > > Thus, the process was running through both route-maps. As per your
> > > statement, it should only be the MED of 300 for all prefixes
> >containing
> > > AS 99...
> > >
> > > Hope I could help.
> > >
> > > Cheers
> > > Marcus
> > >
> > >
> > > -------- Original Message --------
> > > Subject: RE: Route-Map Logic (Example from networkers 2000)
> >(28-Sep-2003
> > > 14:12)
> > > From: Ken.Farrington@barclayscapital.com
> > > To: navaid@rogers.com
> > >
> > > > Yes, they are for different routes.
> > > >
> > > > I am just confused then, on how the route-maps work, so, if you
> > > > set
> > > an
> > > > attrib on prefix A, lets say, then you cant do anything else
> > > > with a
> > > route
> > > > map to that prefix?
> > > >
> > > > ? Im sure there are some "route-map Kings" on this list
> > > > somewhere?
> >
> > > >
> > > > Many thx for the input Navaid :)
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: navaid@rogers.com [mailto:navaid@rogers.com]
> > > > Sent: 28 September 2003 12:55
> > > > To: Ken.Farrington@barclayscapital.com; ccielab@groupstudy.com
> > > > Cc: kenfarrington@yahoo.com
> > > > Subject: Re: Route-Map Logic (Example from networkers 2000)
> > > >
> > > >
> > > > Ken,
> > > > Are you setting community attribute and next-hop for same route.
> > > > If it is for different routes. I think it will work because
> >route-map
> > > is
> > > > applied for each route one by one.
> > > >
> > > > Navaid.
> > > >
> > > >
> > > > >
> > > > > From: Ken.Farrington@barclayscapital.com
> > > > > Date: 2003/09/28 Sun AM 06:54:05 EDT
> > > > > To: ccielab@groupstudy.com
> > > > > CC: kenfarrington@yahoo.com
> > > > > Subject: Route-Map Logic (Example from networkers 2000)
> > > > >
> > > > > All,
> > > > >
> > > > > I am a little confused about the route-map logic that Cisco
> > > > > use. In their example from networkers 2000, they say (note the
> > > > > first
> >line
> > > in
> > > > the
> > > > > table)
> > > > > that if in your route-map, you have a hit on a permit and set
> > > > > an
> > > > attribute,
> > > > > the
> > > > > route-map will exit?
> > > > >
> > > > > +--------------------------------------------------------------+
> > > > > | ROUTE-MAP | MATCH CLAUSE/ | ACCEPT ROUTE and | EXIT |
> > > > > | STANZA | PREFIX-LIST | SET ATTRIBUTE | ROUTE-MAP |
> > > > > +-----------+-----------------+--------------------+-----------+
> > > > > | Permit | Yes/Permit | Yes | Yes |
> > > > > | | | | |
> > > > > | Permit | No/Deny | No | No |
> > > > > | | | | |
> > > > > | Deny | Yes/Permit | No | Yes |
> > > > > | | | | |
> > > > > | Deny | No/Deny | No | No |
> > > > > +-----------+-----------------+--------------------+-----------+
> > > > >
> > > > >
> > > > >
> > > > > So I have a route map doing two things for BGP.
> > > > > 1. Setting the next-hop attrib
> > > > > 2. Setting the community
> > > > >
> > > > > But my route map does not exit after the first hit (permit 10)
> > > > > to
> > > set the
> > > > > next hop.
> > > > > It does continue to go onto 20 and set my community.
> > > > >
> > > > > Can someone please clarify this for me.
> > > > >
> > > > > ****Will it always go onto the next route-map statment if
> > > > > there is
> > > one?
> > > > ****
> > > > >
> > > > >
> > > > >
> > > > > !
> > > > > ip prefix-list BGP-COMM-LIST seq 5 permit 1.1.1.0/24 ip
> > > > > prefix-list BGP-COMM-LIST seq 10 permit 2.2.2.0/24 !
> > > > > ip prefix-list BGP-SNH-LIST seq 5 permit 3.3.3.3/32
> > > > > ip prefix-list BGP-SNH-LIST seq 10 permit 4.4.4.4/32
> > > > > !
> > > > > !
> > > > > route-map BGP-ATTRIB permit 10
> > > > > match ip address prefix-list BGP-SNH-LIST
> > > > > set ip next-hop 142.220.10.1
> > > > > !
> > > > > route-map BGP-ATTRIB permit 20
> > > > > match ip address prefix-list BGP-COMM-LIST
> > > > > set community local-AS
> > > > > !
> > > > > route-map BGP-ATTRIB permit 30
> > > > > !
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> >---------------------------------------------------------------------
> >--
> >-
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> > > > > web site at http://www.barcap.com.
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> >---------------------------------------------------------------------
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> >-
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> > > > >
> > >
> >_____________________________________________________________________
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> > > from:
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> > > > 1
> > > >
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> > >
> >_____________________________________________________________________
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> > > > Please help support GroupStudy by purchasing your study
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> > >
> > > To: Ken.Farrington@barclayscapital.com
> > > Cc: ccielab@groupstudy.com
> > >
> > > ***Get your CCIE and a FREE vacation: Shop.GroupStudy.com***
> > >
> >_____________________________________________________________________
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> >
> >To: jhays@jtan.com
> > Ken.Farrington@barclayscapital.com
> >Cc: ccielab@groupstudy.com
> >
> >***Get your CCIE and a FREE vacation: Shop.GroupStudy.com***
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