From: ccie2be (ccie2be@nyc.rr.com)
Date: Sun Aug 08 2004 - 00:15:05 GMT-3
Why? It looks like it's working. Will session go down or flap if config is
left as is?
----- Original Message -----
From: "Ty" <tycampbell@comcast.net>
To: "Larry Metzger" <larrymetzger@sbcglobal.net>; "'Group Study'"
<ccielab@groupstudy.com>
Sent: Saturday, August 07, 2004 10:54 PM
Subject: Re: BGP Update Source
> Larry,
>
> You will need update-source loopback 0 on router 1 for neighbor
150.50.17.2
>
> ie...
>
> neighbor 150.50.17.2 update-source loopback 0
>
> I am familiar with this lab that you are speaking of.
>
> This is because of R2 connecting to R1 via R1 loopback.
>
> You will not need update-source on R2 for R1
>
> HTH!
>
> Ty
>
> ----- Original Message -----
> From: "Larry Metzger" <larrymetzger@sbcglobal.net>
> To: "'Group Study'" <ccielab@groupstudy.com>
> Sent: Saturday, August 07, 2004 9:45 PM
> Subject: RE: BGP Update Source
>
>
> > I'll respond here for both CCIE2BE and William. If you're not into BGP
> > ignore this!!!!!
> >
> > I understand the concepts very well. However, I have to say that in the
> > lab it works as I have described and the following should show what I am
> > talking about.
> >
> > For those interested in a full network diagram...I'm using IPExpert lab
> > number 9 on BGP. I have a router R1 (1605 with 12.2(15)T13) connecting
> > over Ethernet to R2 (2503 with 12.2(24b)). The R1 has a loopback0 IP
> > 200.0.0.1 that will be called as the neighbor by R2. R1 calls neighbor
> > using Ethernet address. WITH OR WITHOUT the update-source command
> > connections are created and the systems work with BGP. What follows is
> > lengthy.
> >
> > hostname r1
> > !
> > interface Loopback0
> > ip address 200.0.0.1 255.255.255.255
> > !
> > interface Ethernet0
> > ip address 150.50.17.1 255.255.255.0
> > !
> > router bgp 100
> > no synchronization
> > bgp router-id 200.0.0.1
> > bgp log-neighbor-changes
> > network 192.168.10.0 mask 255.255.255.240
> > network 192.168.10.16 mask 255.255.255.240
> > network 192.168.20.32 mask 255.255.255.240
> > network 192.168.20.48 mask 255.255.255.240
> > aggregate-address 192.168.10.0 255.255.255.0 summary-only
> > aggregate-address 192.168.20.0 255.255.255.0 summary-only
> > neighbor 150.50.17.2 remote-as 200
> > no auto-summary
> > !
> >
> > r1#clear ip bgp *
> > r1#
> > *Mar 1 00:05:01.175: %BGP-5-ADJCHANGE: neighbor 150.50.17.2 Down User
> > reset
> > r1#
> > *Mar 1 00:05:43.513: %BGP-5-ADJCHANGE: neighbor 150.50.17.2 Up
> > r1#sh ip bgp nei
> > BGP neighbor is 150.50.17.2, remote AS 200, external link
> > BGP version 4, remote router ID 200.0.0.2
> > BGP state = Established, up for 00:01:16
> > Last read 00:00:15, hold time is 180, keepalive interval is 60 seconds
> > Neighbor capabilities:
> > Route refresh: advertised and received(old & new)
> > Address family IPv4 Unicast: advertised and received
> > Message statistics:
> > InQ depth is 0
> > OutQ depth is 0
> > Sent Rcvd
> > Opens: 2 2
> > Notifications: 0 0
> > Updates: 2 4
> > Keepalives: 10 10
> > Route Refresh: 0 0
> > Total: 14 16
> > Default minimum time between advertisement runs is 30 seconds
> >
> > For address family: IPv4 Unicast
> > BGP table version 14, neighbor version 14
> > Index 1, Offset 0, Mask 0x2
> > Sent Rcvd
> > Prefix activity: ---- ----
> > Prefixes Current: 2 3 (Consumes 144 bytes)
> > Prefixes Total: 2 3
> > Implicit Withdraw: 0 0
> > Explicit Withdraw: 0 0
> > Used as bestpath: n/a 3
> > Used as multipath: n/a 0
> >
> > Outbound Inbound
> > Local Policy Denied Prefixes: -------- -------
> > Bestpath from this peer: 3 n/a
> > Suppressed due to dampening: 4 n/a
> > Total: 7 0
> > Number of NLRIs in the update sent: max 2, min 0
> >
> > Connections established 2; dropped 1
> > Last reset 00:02:00, due to User reset
> > Connection state is ESTAB, I/O status: 1, unread input bytes: 0
> > Local host: 200.0.0.1, Local port: 179
> > Foreign host: 150.50.17.2, Foreign port: 11003
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x67EE8):
> > Timer Starts Wakeups Next
> > Retrans 7 0 0x0
> > TimeWait 0 0 0x0
> > AckHold 5 1 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > PmtuAger 0 0 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 3216124146 snduna: 3216124336 sndnxt: 3216124336 sndwnd:
> > 16195
> > irs: 1986047258 rcvnxt: 1986047484 rcvwnd: 16159 delrcvwnd:
> > 225
> >
> > SRTT: 182 ms, RTTO: 1073 ms, RTV: 891 ms, KRTT: 0 ms
> > minRTT: 4 ms, maxRTT: 300 ms, ACK hold: 200 ms
> > Flags: passive open, nagle, gen tcbs
> > --More--
> > Datagrams (max data segment is 536 bytes):
> > Rcvd: 10 (out of order: 0), with data: 5, total data bytes: 225
> > Sent: 8 (retransmit: 0, fastretransmit: 0), with data: 6, total data
> > bytes: 189
> > r1#sh ip bgp
> > BGP table version is 14, local router ID is 200.0.0.1
> > Status codes: s suppressed, d damped, h history, * valid, > best, i -
> > internal,
> > r RIB-failure, S Stale
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric LocPrf Weight Path
> > *> 10.1.1.0/24 150.50.17.2 0 200 300 310
> > 320 330 i
> > s> 192.168.10.0/28 0.0.0.0 0 32768 i
> > *> 192.168.10.0 0.0.0.0 32768 i
> > s> 192.168.10.16/28 0.0.0.0 0 32768 i
> > *> 192.168.20.0 0.0.0.0 32768 i
> > s> 192.168.20.32/28 0.0.0.0 0 32768 i
> > s> 192.168.20.48/28 0.0.0.0 0 32768 i
> > *> 200.0.0.4/32 150.50.17.2 0 200 300 310
> > 320 330 i
> > *> 200.0.0.6/32 150.50.17.2 0 200 i
> > r1#sh tcp
> >
> > Stand-alone TCP connection from host 150.50.17.2
> > Connection state is ESTAB, I/O status: 1, unread input bytes: 0
> > Local host: 200.0.0.1, Local port: 179
> > Foreign host: 150.50.17.2, Foreign port: 11003
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x69CCC):
> > Timer Starts Wakeups Next
> > Retrans 7 0 0x0
> > TimeWait 0 0 0x0
> > AckHold 5 1 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > PmtuAger 0 0 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 3216124146 snduna: 3216124336 sndnxt: 3216124336 sndwnd:
> > 16195
> > irs: 1986047258 rcvnxt: 1986047484 rcvwnd: 16159 delrcvwnd:
> > 225
> >
> > SRTT: 182 ms, RTTO: 1073 ms, RTV: 891 ms, KRTT: 0 ms
> > minRTT: 4 ms, maxRTT: 300 ms, ACK hold: 200 ms
> > Flags: passive open, nagle, gen tcbs
> >
> > Datagrams (max data segment is 536 bytes):
> > Rcvd: 10 (out of order: 0), with data: 5, total data bytes: 225
> > Sent: 8 (retransmit: 0, fastretransmit: 0), with data: 6, total data
> > bytes: 189
> > r1#
> > *************************************************
> > hostname r2
> > !
> > interface Ethernet0
> > ip address 150.50.17.2 255.255.255.0
> > !
> > router bgp 65256
> > no synchronization
> > bgp router-id 200.0.0.2
> > bgp log-neighbor-changes
> > bgp confederation identifier 200
> > bgp confederation peers 65078
> > neighbor 150.50.24.4 remote-as 300
> > neighbor 150.50.24.4 route-map task11 out
> > neighbor 150.50.100.5 remote-as 65256
> > neighbor 150.50.100.5 next-hop-self
> > neighbor 150.50.100.5 route-map task10 out
> > neighbor 200.0.0.1 remote-as 100
> > neighbor 200.0.0.1 ebgp-multihop 2
> > no auto-summary
> > !
> > ip route 200.0.0.1 255.255.255.255 150.50.17.1
> >
> >
> > sh ip bgp nei 200.0.0.1
> > BGP neighbor is 200.0.0.1, remote AS 100, external link
> > BGP version 4, remote router ID 200.0.0.1
> > BGP state = Established, up for 00:02:07
> > Last read 00:00:08, hold time is 180, keepalive interval is 60 seconds
> > Neighbor capabilities:
> > Route refresh: advertised and received(old & new)
> > Address family IPv4 Unicast: advertised and received
> > Message statistics:
> > InQ depth is 0
> > OutQ depth is 0
> > Sent Rcvd
> > Opens: 2 2
> > Notifications: 0 0
> > Updates: 4 2
> > Keepalives: 11 11
> > Route Refresh: 0 0
> > Total: 17 15
> > Default minimum time between advertisement runs is 30 seconds
> >
> > For address family: IPv4 Unicast
> > BGP table version 12, neighbor version 12
> > Index 3, Offset 0, Mask 0x8
> > Sent Rcvd
> > Prefix activity: ---- ----
> > Prefixes Current: 3 2 (Consumes 72 bytes)
> > Prefixes Total: 3 2
> > Implicit Withdraw: 0 0
> > Explicit Withdraw: 0 0
> > Used as bestpath: n/a 2
> > Used as multipath: n/a 0
> >
> > Outbound Inbound
> > Local Policy Denied Prefixes: -------- -------
> > Well-known Community: 2 n/a
> > Bestpath from this peer: 2 n/a
> > Total: 4 0
> > Number of NLRIs in the update sent: max 2, min 0
> >
> > Connections established 2; dropped 1
> > Last reset 00:02:49, due to Peer closed the session
> > External BGP neighbor may be up to 2 hops away.
> > --More-- Connection state is ESTAB, I/O
> > status: 1, unread input bytes: 0
> > Local host: 150.50.17.2, Local port: 11003
> > Foreign host: 200.0.0.1, Foreign port: 179
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x87ED4):
> > Timer Starts Wakeups Next
> > Retrans 7 0 0x0
> > TimeWait 0 0 0x0
> > AckHold 7 4 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > PmtuAger 0 0 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 1986047258 snduna: 1986047503 sndnxt: 1986047503 sndwnd:
> > 16140
> > irs: 3216124146 rcvnxt: 3216124355 rcvwnd: 16176 delrcvwnd:
> > 208
> >
> > SRTT: 182 ms, RTTO: 1073 ms, RTV: 891 ms, KRTT: 0 ms
> > minRTT: 8 ms, maxRTT: 300 ms, ACK hold: 200 ms
> > Flags: higher precedence, nagle
> > --More--
> > Datagrams (max data segment is 536 bytes):
> > Rcvd: 10 (out of order: 0), with data: 7, total data bytes: 208
> > Sent: 12 (retransmit: 0, fastretransmit: 0), with data: 6, total data
> > bytes: 244
> > r2#sh ip bgp
> > BGP table version is 12, local router ID is 200.0.0.2
> > 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
> > *>i8.8.8.0/24 150.50.100.5 0 100 0 (65078) ?
> > *> 10.1.1.0/24 150.50.24.4 0 0 300 310 320
> > 330 i
> > *>i150.50.4.0/24 150.50.100.5 20 100 0 (65078) ?
> > *> 192.168.10.0 200.0.0.1 0 0 100 i
> > *> 192.168.20.0 200.0.0.1 0 0 100 i
> > *> 200.0.0.4/32 150.50.24.4 0 0 300 310 320
> > 330 i
> > *>i200.0.0.6/32 150.50.100.6 0 100 0 i
> > r2#sh tcp
> >
> > Stand-alone TCP connection to host 150.50.100.5
> > Connection state is ESTAB, I/O status: 1, unread input bytes: 0
> > Local host: 150.50.100.2, Local port: 11000
> > Foreign host: 150.50.100.5, Foreign port: 179
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x8A168):
> > Timer Starts Wakeups Next
> > Retrans 16 0 0x0
> > TimeWait 0 0 0x0
> > AckHold 10 6 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > PmtuAger 0 0 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 3993375966 snduna: 3993376441 sndnxt: 3993376441 sndwnd:
> > 15910
> > irs: 1772481955 rcvnxt: 1772482393 rcvwnd: 15947 delrcvwnd:
> > 437
> >
> > SRTT: 265 ms, RTTO: 545 ms, RTV: 280 ms, KRTT: 0 ms
> > --More-- minRTT: 8 ms, maxRTT: 308 ms, ACK
> > hold: 200 ms
> > Flags: higher precedence, nagle
> >
> > Datagrams (max data segment is 1460 bytes):
> > Rcvd: 19 (out of order: 0), with data: 10, total data bytes: 437
> > Sent: 23 (retransmit: 0, fastretransmit: 0), with data: 15, total data
> > bytes: 474
> >
> > Stand-alone TCP connection to host 200.0.0.1
> > Connection state is ESTAB, I/O status: 1, unread input bytes: 0
> > Local host: 150.50.17.2, Local port: 11003
> > Foreign host: 200.0.0.1, Foreign port: 179
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x8AA78):
> > Timer Starts Wakeups Next
> > Retrans 7 0 0x0
> > TimeWait 0 0 0x0
> > AckHold 7 4 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > --More-- PmtuAger 0 0
> > 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 1986047258 snduna: 1986047503 sndnxt: 1986047503 sndwnd:
> > 16140
> > irs: 3216124146 rcvnxt: 3216124355 rcvwnd: 16176 delrcvwnd:
> > 208
> >
> > SRTT: 182 ms, RTTO: 1073 ms, RTV: 891 ms, KRTT: 0 ms
> > minRTT: 8 ms, maxRTT: 300 ms, ACK hold: 200 ms
> > Flags: higher precedence, nagle
> >
> > Datagrams (max data segment is 536 bytes):
> > Rcvd: 10 (out of order: 0), with data: 7, total data bytes: 208
> > Sent: 12 (retransmit: 0, fastretransmit: 0), with data: 6, total data
> > bytes: 244
> >
> > Stand-alone TCP connection to host 150.50.24.4
> > Connection state is ESTAB, I/O status: 1, unread input bytes: 0
> > Local host: 150.50.24.2, Local port: 11001
> > Foreign host: 150.50.24.4, Foreign port: 179
> >
> > Enqueued packets for retransmit: 0, input: 0 mis-ordered: 0 (0 bytes)
> >
> > Event Timers (current time is 0x8B298):
> > Timer Starts Wakeups Next
> > --More-- Retrans 13 0
> > 0x0
> > TimeWait 0 0 0x0
> > AckHold 12 7 0x0
> > SendWnd 0 0 0x0
> > KeepAlive 0 0 0x0
> > GiveUp 0 0 0x0
> > PmtuAger 0 0 0x0
> > DeadWait 0 0 0x0
> >
> > iss: 2325565762 snduna: 2325566044 sndnxt: 2325566044 sndwnd:
> > 16103
> > irs: 1896377811 rcvnxt: 1896378110 rcvwnd: 16086 delrcvwnd:
> > 298
> >
> > SRTT: 253 ms, RTTO: 657 ms, RTV: 404 ms, KRTT: 0 ms
> > minRTT: 24 ms, maxRTT: 404 ms, ACK hold: 200 ms
> > Flags: higher precedence, nagle
> >
> > Datagrams (max data segment is 1460 bytes):
> > Rcvd: 18 (out of order: 0), with data: 12, total data bytes: 298
> > Sent: 21 (retransmit: 0, fastretransmit: 0), with data: 12, total data
> > bytes: 281
> > r2
> >
> > -----Original Message-----
> > From: William Chen [mailto:kwchen@netvigator.com]
> > Sent: Saturday, August 07, 2004 7:07 PM
> > To: Larry Metzger; Group Study
> > Subject: Re: BGP Update Source
> >
> > Hi Larry,
> >
> > I think update-source is necessary, if you want to form the BGP peer
> > using loopback address. It is because, when BGP get reply from neighbor,
> > it
> > will expected the source address of the reply is matching with the
> > address
> > you set in the neighbor statement. It is impossible that the reply
> > message
> > from the BGP peer use loopback as source address (it will use the
> > outging
> > physical address as the source address for most time), unless you told
> > the
> > router to do so (i.e. using the update-source command).
> >
> > I will appreciate if you send us the configuration and also state
> > which
> > IOS version you used.
> >
> > HTH,
> > William
> >
> > ----- Original Message -----
> > From: "Larry Metzger" <larrymetzger@sbcglobal.net>
> > To: "Group Study" <ccielab@groupstudy.com>
> > Sent: Sunday, August 08, 2004 8:10 AM
> > Subject: BGP Update Source
> >
> >
> > > I am working on BGP configurations. I have Router1 (as100) and
> > Router2
> > > (as200). I'm using the loopback on Router1 for the neighbor
> > statement.
> > > The recommendation is to add "neigh R2 update-source loop0" I have
> > > configured these routers with and without the update source and
> > > everything works fine either way (sh ip bgp, sh ip bgp nei, sh tcp).
> > Is
> > > it necessary? What problems will it cause if you don't change the
> > > update-source?
> > >
> > > Larry
> > >
> > >
> > _______________________________________________________________________
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