From: Narvaez, Pablo (Pablo.Narvaez@xxxxxxxxxxxxx)
Date: Sat Apr 06 2002 - 21:19:28 GMT-3
I am Guy, but seems like I get some lag or something hehe .... sometimes I just
do not receive my own e-mail when replying or posting and some other times I s
ee the answer to my question before my posting ....
I think that's normal and I'm so glad this list is up no metter what :-)
-----Original Message-----
From: Lupi, Guy [mailto:Guy.Lupi@eurekaggn.com]
Sent: Sabado, 06 de Abril de 2002 05:41 p.m.
To: Narvaez, Pablo; ying chang; Upp_and_Upp@hotmail.com;
ccielab@groupstudy.com
Subject: RE: BGP MED - again
Just out of curiosity, is anyone seeing the messages I send? Thanks.
~-----Original Message-----
~From: Narvaez, Pablo [mailto:Pablo.Narvaez@getronics.com]
~Sent: Saturday, April 06, 2002 6:28 PM
~To: ying chang; Upp_and_Upp@hotmail.com; ccielab@groupstudy.com
~Subject: RE: BGP MED - again
~
~
~ummm I think your route is damnt hehe .... sorry about that.
~ummmm if you check the attribs between them you'll see that
~r3 is choosing "theorically" the worst route. Weight is the
~same, Local-Pref is better thru 26.1.1.2, asp-path is shorter
~thru 26.1.1.2 and also med is lower .... can you do a "show ip
~bgp 192.168.1.0" ... at the first sight I wonder why that
~route is going thru 10.1.1.1 instead of 26.1.1.2.
~
~
~The only thing that comes to my head is the next hop is not
~available or if that route is internal, you have sync enabled
~and that route is not known thru IGP.
~
~hockito :o
~
~-----Original Message-----
~From: ying chang [mailto:ying_c@hotmail.com]
~Sent: Sabado, 06 de Abril de 2002 05:17 p.m.
~To: Narvaez, Pablo; Upp_and_Upp@hotmail.com; ccielab@groupstudy.com
~Subject: RE: BGP MED - again
~
~
~Hi hockito,
~
~Sorry, you are right. Can you explain why I get the following
~(192.168.1.0)
~which is the route from R1:
~
~r3#sib
~BGP table version is 5, local router ID is 36.1.1.3
~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
~*>i26.1.1.0/24 36.1.1.6 0 100 0 i
~*> 36.1.1.0/24 0.0.0.0 0 32768 i
~* i 36.1.1.6 0 100 0 i
~* i192.168.1.0 26.1.1.2 20 100 0 1 i
~*> 10.1.1.1 30 0 1 1 1 i
~r3#
~
~Thanks,
~Chang
~
~
~>From: "Narvaez, Pablo" <Pablo.Narvaez@getronics.com>
~>Reply-To: "Narvaez, Pablo" <Pablo.Narvaez@getronics.com>
~>To: "ying chang" <ying_c@hotmail.com>,
~<Upp_and_Upp@hotmail.com>,
~><ccielab@groupstudy.com>
~>Subject: RE: BGP MED - again
~>Date: Sat, 6 Apr 2002 16:55:11 -0600
~>
~>ummm isn't as-path compared first that ibgp vs ebgp ?
~>
~>I'll ommit some attribs checked in between for path
~selection, but isn't
~>like this: (?)
~>
~>- weight
~>- local-pref
~>- as-path
~>- med
~>- ebgp vs ibgp
~>
~>??
~>
~>So that would give us as-path comparision before ebgp-igrp, correct?
~>
~>If you prepend from r2 to r3 thru r6, I think r3 will send that route
~>prepended, which cause that r1 selects that route thru r2.
~This way you'll
~>have touched only r2 and r1 will see r1-r2.
~>
~>Am I right?
~>
~>hockito
~>
~>
~>
~>
~>-----Original Message-----
~>From: ying chang [mailto:ying_c@hotmail.com]
~>Sent: Sabado, 06 de Abril de 2002 04:29 p.m.
~>To: Upp_and_Upp@hotmail.com; ccielab@groupstudy.com
~>Subject: Re: BGP MED - again
~>
~>
~>Hi Sean,
~>
~>Thanks. Please check R3's BGP table. My topology is
~>
~> -----R1(AS1)-----
~> | |
~> R2 R3
~> |----R6---------| (R2, R3, R6 are in AS236)
~>
~>As you can see MED is comparision is skipped. as-path will
~not do anything
~>for this case, because ebgp route is preferred as we've seen
~from Peter's
~>example - as-path comparision come after ebgp-ibgp comparision.
~>
~>Thanks,
~>Chang
~>
~>R1: AS1 (ISP router)
~>
~>interface Loopback0
~>ip address 192.168.1.1 255.255.255.0
~>!
~>interface Ethernet0
~>no ip address
~>shutdown
~>!
~>interface Serial0
~>ip address 10.1.1.1 255.255.255.0
~>encapsulation frame-relay
~>no fair-queue
~>frame-relay map ip 10.1.1.2 110 broadcast
~>frame-relay map ip 10.1.1.3 120 broadcast
~>no frame-relay inverse-arp
~>!
~>router bgp 1
~>bgp log-neighbor-changes
~>network 192.168.1.0
~>neighbor 10.1.1.2 remote-as 236
~>neighbor 10.1.1.2 soft-reconfiguration inbound
~>neighbor 10.1.1.2 route-map set-med1 out
~>neighbor 10.1.1.3 remote-as 236
~>neighbor 10.1.1.3 soft-reconfiguration inbound
~>neighbor 10.1.1.3 route-map set-med2 out
~>!
~>!
~>route-map set-med2 permit 10
~>set metric 30
~>set as-path prepend 1 1
~>!
~>route-map set-med1 permit 10
~>set metric 20
~>!
~>
~>R2: (AS236, border router 1 to R1)
~>!
~>interface Ethernet1
~>ip address 26.1.1.2 255.255.255.0
~>!
~>interface Serial0
~>ip address 10.1.1.2 255.255.255.0
~>encapsulation frame-relay
~>no fair-queue
~>frame-relay map ip 10.1.1.1 111 broadcast
~>frame-relay map ip 10.1.1.3 111 broadcast
~>!
~>router ospf 100
~>router-id 26.1.1.2
~>log-adjacency-changes
~>passive-interface default
~>no passive-interface Ethernet1
~>no passive-interface Serial0
~>network 0.0.0.0 255.255.255.255 area 0
~>!
~>router bgp 236
~>bgp router-id 26.1.1.2
~>bgp always-compare-med
~>bgp log-neighbor-changes
~>neighbor 10.1.1.1 remote-as 1
~>neighbor 10.1.1.1 soft-reconfiguration inbound
~>neighbor 26.1.1.6 remote-as 236
~>neighbor 26.1.1.6 next-hop-self
~>neighbor 36.1.1.3 remote-as 236
~>neighbor 36.1.1.3 next-hop-self
~>neighbor 36.1.1.3 soft-reconfiguration inbound
~>!
~>
~>R3: (AS236, border router 2 to R1)
~>
~>!
~>interface Ethernet0
~>ip address 36.1.1.3 255.255.255.0
~>!
~>interface Serial0
~>ip address 10.1.1.3 255.255.255.0
~>encapsulation frame-relay
~>no fair-queue
~>frame-relay map ip 10.1.1.1 121 broadcast
~>frame-relay map ip 10.1.1.2 121 broadcast
~>!
~>!
~>router ospf 100
~>router-id 36.1.1.3
~>log-adjacency-changes
~>passive-interface default
~>no passive-interface Ethernet0
~>no passive-interface Serial0
~>network 0.0.0.0 255.255.255.255 area 0
~>!
~>router bgp 236
~>bgp always-compare-med
~>bgp log-neighbor-changes
~>bgp always-compare-med
~>network 36.1.1.0 mask 255.255.255.0
~>neighbor 10.1.1.1 remote-as 1
~>neighbor 10.1.1.1 soft-reconfiguration inbound
~>neighbor 26.1.1.2 remote-as 236
~>neighbor 26.1.1.2 next-hop-self
~>neighbor 26.1.1.2 soft-reconfiguration inbound
~>neighbor 36.1.1.6 remote-as 236
~>neighbor 36.1.1.6 next-hop-self
~>neighbor 36.1.1.6 soft-reconfiguration inbound
~>!
~>
~>(R6: internal router, IBGP to R2 and R3 only)
~>!
~>interface Ethernet0
~>ip address 26.1.1.6 255.255.255.0
~>!
~>interface Ethernet1
~>ip address 36.1.1.6 255.255.255.0
~>!
~>!
~>router ospf 100
~>router-id 36.1.1.6
~>log-adjacency-changes
~>passive-interface default
~>no passive-interface Ethernet0
~>no passive-interface Ethernet1
~>network 0.0.0.0 255.255.255.255 area 0
~>!
~>router bgp 236
~>no synchronization
~>bgp router-id 36.1.1.6
~>bgp always-compare-med
~>bgp log-neighbor-changes
~>bgp deterministic-med
~>network 26.1.1.0 mask 255.255.255.0
~>network 36.1.1.0 mask 255.255.255.0
~>neighbor 26.1.1.2 remote-as 236
~>neighbor 26.1.1.2 soft-reconfiguration inbound
~>neighbor 36.1.1.3 remote-as 236
~>neighbor 36.1.1.3 soft-reconfiguration inbound
~>!
~>-------------------------------------------------------
~>BGP tables
~>-------------------------------------------------------
~>r1#sib
~>BGP table version is 25, local router ID is 192.168.1.1
~>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
~>* 26.1.1.0/24 10.1.1.2 0 236 i
~>*> 10.1.1.3 0 236 i
~>* 36.1.1.0/24 10.1.1.2 0 236 i
~>*> 10.1.1.3 0 0 236 i
~>*> 192.168.1.0 0.0.0.0 0 32768 i
~>r1#
~>termserv#2
~>[Resuming connection 2 to r2 ... ]
~>
~>r2#sib
~>BGP table version is 4, local router ID is 26.1.1.2
~>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
~>*>i26.1.1.0/24 26.1.1.6 0 100 0 i
~>*>i36.1.1.0/24 26.1.1.6 0 100 0 i
~>* i 36.1.1.3 0 100 0 i
~>*> 192.168.1.0 10.1.1.1 20 0 1 i
~>* i 36.1.1.3 30 100 0 1 1 1 i
~>r2#
~>termserv#3
~>[Resuming connection 3 to r3 ... ]
~>
~>r3#sib
~>BGP table version is 5, local router ID is 36.1.1.3
~>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
~>*>i26.1.1.0/24 36.1.1.6 0 100 0 i
~>*> 36.1.1.0/24 0.0.0.0 0 32768 i
~>* i 36.1.1.6 0 100 0 i
~>* i192.168.1.0 26.1.1.2 20 100 0 1 i
~>*> 10.1.1.1 30 0 1 1 1 i
~>r3#
~>termserv#6
~>[Resuming connection 6 to r6 ... ]
~>
~>r6#sib
~>BGP table version is 8, local router ID is 36.1.1.6
~>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
~>*> 26.1.1.0/24 0.0.0.0 0 32768 i
~>*> 36.1.1.0/24 0.0.0.0 0 32768 i
~>* i 36.1.1.3 0 100 0 i
~>*>i192.168.1.0 26.1.1.2 20 100 0 1 i
~>* i 36.1.1.3 30 100 0 1 1 1 i
~>r6#
~>
~>
~>
~> >From: "Sean C." <Upp_and_Upp@hotmail.com>
~> >Reply-To: "Sean C." <Upp_and_Upp@hotmail.com>
~> >To: "ying chang" <ying_c@hotmail.com>, <ccielab@groupstudy.com>
~> >Subject: Re: BGP MED - again
~> >Date: Sat, 6 Apr 2002 16:50:54 -0800
~> >
~> >Hi Chang,
~> >
~> >Concerning your question of how to manipulate routes so the
~routes will
~>be
~> >preferred on the R1-R3 link over R2-R3 routes while not
~being able to
~> >change
~> >the configs on R1 and R3 (in other words - you can only
~work on R3) - add
~>a
~> >route-map on R3 and prepend R3's own AS# to routes being
~advertised to
~>R2.
~> >Since shorter AS paths are preferred, the routes will all
~come in on the
~> >R1-R3 route which has a shorter AS path. Plus, you don't have to
~> >manipulate anything on R2 and R1.
~> >
~> >Hope this helps,
~> >Sean
~> >----- Original Message -----
~> >From: "ying chang" <ying_c@hotmail.com>
~> >To: <dan_schaw@yahoo.com>; <jgraun@attbi.com>; <pdostal@724.com>;
~> ><ccielab@groupstudy.com>
~> >Sent: Saturday, April 06, 2002 12:47 PM
~> >Subject: RE: BGP MED - again
~> >
~> >
~> >Well, "bgp always compared Med" would not work help in this
~case as they
~> >both come from AS1.
~> >
~> >There are two web pages are helpful:
~> >
~> >http://www.cisco.com/warp/public/459/bgp-med.html
~> >http://www.cisco.com/warp/public/459/37.html
~> >
~> >Here's my question, if we stick on the original problem,
~which is we are
~> >trying to tell AS1 to prefer R1-R3 route instead of R2-R3
~route, how can
~>we
~> >do it without changing anything on either R1 or R2? Can it
~be done? In
~> >simple term, R1 and R2 are proctor's routers, and you have
~to work on R3
~>to
~> >make R1 and R2 always prefer R1-R3 route.
~> >
~> >Thanks,
~> >Chang
~> >
~> >
~> > >From: Muhamamd Durrani <dan_schaw@yahoo.com>
~> > >Reply-To: Muhamamd Durrani <dan_schaw@yahoo.com>
~> > >To: Jason <jgraun@attbi.com>, "'Peter Dostal'" <pdostal@724.com>,
~> > >ccielab@groupstudy.com
~> > >Subject: RE: BGP MED
~> > >Date: Fri, 5 Apr 2002 23:00:57 -0800 (PST)
~> > >
~> > >you should use "bgp always compared Med " command to
~> > >force BGP to compare MED for destination from
~> > >Different AS systems . By default BGP donot compare
~> > >MED for same destinations from neighbors from
~> > >different AS.
~> > >
~> > >So R2 must have this command and than verify ur result
~> > >....
~> > >
~> > >Regards,
~> > >Muhammad
~> > >
~> > >
~> > >--- Jason <jgraun@attbi.com> wrote:
~> > > > Well iBGP as an Admin distance of 200 while eBGP has
~> > > > an admin distance
~> > > > of 20
~> > > >
~> > > > -----Original Message-----
~> > > > From: nobody@groupstudy.com
~> > > > [mailto:nobody@groupstudy.com] On Behalf Of
~> > > > Peter Dostal
~> > > > Sent: Friday, April 05, 2002 6:58 PM
~> > > > To: ccielab@groupstudy.com
~> > > > Subject: BGP MED
~> > > >
~> > > > I have a problem with BGP path selection process.
~> > > > Based on the BGP path
~> > > > selection process I would say that router R2 should
~> > > > choose iBGP path
~> > > > over
~> > > > eBGP (because of lower MED). Any suggestions?
~> > > > Thanks,
~> > > >
~> > > > Peter
~> > > >
~> > > >
~> > > > R1----FrameRelay----R2
~> > > > | |
~> > > > ------Ethernet-------
~> > > > |
~> > > > R3
~> > > >
~> > > > *********************************************
~> > > > hostname R1
~> > > > !
~> > > > interface FastEthernet1/1
~> > > > ip address 192.168.2.3 255.255.255.0
~> > > > !
~> > > > interface Serial1/0
~> > > > ip address 192.168.1.1 255.255.255.0
~> > > > encapsulation frame-relay
~> > > > no keepalive
~> > > > no fair-queue
~> > > > frame-relay interface-dlci 100
~> > > > !
~> > > > router bgp 2
~> > > > bgp log-neighbor-changes
~> > > > neighbor 192.168.1.2 remote-as 2
~> > > > neighbor 192.168.1.2 next-hop-self
~> > > > neighbor 192.168.2.1 remote-as 1
~> > > > neighbor 192.168.2.1 route-map BGP_MAP in
~> > > > no auto-summary
~> > > > !
~> > > > route-map BGP_MAP permit 10
~> > > > set local-preference 100
~> > > >
~> > > > *********************************************
~> > > > hostname R2
~> > > > !
~> > > > interface FastEthernet0/0
~> > > > ip address 192.168.2.2 255.255.255.0
~> > > > !
~> > > > interface Serial0/0
~> > > > ip address 192.168.1.2 255.255.255.252
~> > > > encapsulation frame-relay
~> > > > no keepalive
~> > > > no fair-queue
~> > > > frame-relay interface-dlci 100
~> > > > !
~> > > > router bgp 2
~> > > > bgp log-neighbor-changes
~> > > > neighbor 192.168.1.1 remote-as 2
~> > > > neighbor 192.168.1.1 next-hop-self
~> > > > neighbor 192.168.2.1 remote-as 1
~> > > > neighbor 192.168.2.1 route-map BGP_MAP in
~> > > > no auto-summary
~> > > > !
~> > > > route-map BGP_MAP permit 10
~> > > > set local-preference 100
~> > > > !
~> > > > *********************************************
~> > > > hostname R3
~> > > > !
~> > > > interface FastEthernet0/1
~> > > > ip address 192.168.2.1 255.255.255.0
~> > > > !
~> > > > interface Loopback0
~> > > > ip address 170.2.1.1 255.255.255.240
~> > > > !
~> > > > router bgp 1
~> > > > bgp log-neighbor-changes
~> > > > network 170.2.1.0 mask 255.255.255.240
~> > > > neighbor 192.168.2.2 remote-as 2
~> > > > neighbor 192.168.2.2 route-map BGP_MAP out
~> > > > neighbor 192.168.2.3 remote-as 2
~> > > > no auto-summary
~> > > > !
~> > > > route-map BGP_MAP permit 10
~> > > > set metric 20
~> > > >
~> > > > *********************************************
~> > > > R1#sh ip bgp
~> > > > BGP table version is 8, local router ID is
~> > > > 172.10.1.1
~> > > > 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
~> > > > *> 170.2.1.0/28 192.168.2.1 0
~> > > > 100 0 1 i
~> > > > * i 192.168.1.2 20
~> > > > 100 0 1 i
~> > > > *********************************************
~> > > > R2#sh ip bgp
~> > > > BGP table version is 8, local router ID is
~> > > > 192.168.2.2
~> > > > 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
~> > > > * i170.2.1.0/28 192.168.1.1 0
~> > > > 100 0 1 i
~> > > > *> 192.168.2.1 20
~> > > > 100 0 1 i
~> > > > *********************************************
~> > > >
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 10:57:58 GMT-3