Why are you seeing them as unreachable? That may indicate a different
problem!
R2(config-router)#do sh ip bgp
BGP table version is 7, local router ID is 200.0.0.2
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
*> 192.168.10.0 200.0.0.1 0 0 100 i
*> 192.168.20.0 200.0.0.1 0 0 100 i
R2(config-router)#do ping 192.168.10.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.10.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms
R2(config-router)#do ping 192.168.10.17
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.10.17, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms
R2(config-router)#do ping 192.168.20.33
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.33, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/6/8 ms
R2(config-router)#do ping 192.168.20.49
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.20.49, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/6/8 ms
R2(config-router)#
Scott
_____
From: Suresh Mishra [mailto:[EMAIL PROTECTED]
Sent: Wednesday, June 11, 2008 8:44 AM
To: [EMAIL PROTECTED]; OSL CCIE Routing and Switching Lab Exam
Cc: [EMAIL PROTECTED]
Subject: Re: [OSL | CCIE_RS] EBGP Multihop
Ho Scott,
I tried the same thing using ttl-security. I was able to get the neighbor
relationship up but could not get the routes exchanged as next-hop was
showing unreachable.
Suresh
On 6/10/08, Scott Morris <[EMAIL PROTECTED]> wrote:
Two should work just fine. Does for me anyway.
First, I pasted in the configs from Cat1, R1 and R2 as is. Then waited for
spanning tree. ;)
R2(config-if)#do ping 200.0.0.1 <http://200.0.0.1/>
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.0.0.1 <http://200.0.0.1/> , timeout is
2 seconds:
.....
Success rate is 0 percent (0/5)
R2(config-if)#
*Jun 11 04:01:20.395: %BGP-5-ADJCHANGE: neighbor 200.0.0.1
<http://200.0.0.1/> Up
R2(config-if)#do ping 200.0.0.1 <http://200.0.0.1/>
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.0.0.1 <http://200.0.0.1/> , timeout is
2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms
R2(config-if)#do sh run | s bgp
router bgp 65256
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 200
bgp confederation peers 65078
neighbor 150.50.24.4 <http://150.50.24.4/> remote-as 300
neighbor 150.50.24.4 <http://150.50.24.4/> filter-list 1 out
neighbor 150.50.100.5 <http://150.50.100.5/> remote-as 65256
neighbor 150.50.100.5 <http://150.50.100.5/> next-hop-self
neighbor 150.50.100.5 <http://150.50.100.5/> route-map 200Filter out
neighbor 200.0.0.1 <http://200.0.0.1/> remote-as 100
neighbor 200.0.0.1 <http://200.0.0.1/> ebgp-multihop 3
no auto-summary
<<<Notice here that the multihop is 3 as the solutions have, and see above
where the peer came up>>>
R2(config-if)#router bgp 65256
R2(config-router)#no neigh 200.0.0.1 <http://200.0.0.1/>
R2(config-router)#
*Jun 11 04:02:01.099: %BGP-5-ADJCHANGE: neighbor 200.0.0.1
<http://200.0.0.1/> Down Neighbor deleted
R2(config-router)#do sh run | s bgp
router bgp 65256
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 200
bgp confederation peers 65078
neighbor 150.50.24.4 <http://150.50.24.4/> remote-as 300
neighbor 150.50.24.4 <http://150.50.24.4/> filter-list 1 out
neighbor 150.50.100.5 <http://150.50.100.5/> remote-as 65256
neighbor 150.50.100.5 <http://150.50.100.5/> next-hop-self
neighbor 150.50.100.5 <http://150.50.100.5/> route-map 200Filter out
no auto-summary
R2(config-router)#neigh 200.0.0.1 <http://200.0.0.1/> remote-as 100
R2(config-router)#do sh run | s bgp
router bgp 65256
no synchronization
bgp log-neighbor-changes
bgp confederation identifier 200
bgp confederation peers 65078
neighbor 150.50.24.4 <http://150.50.24.4/> remote-as 300
neighbor 150.50.24.4 <http://150.50.24.4/> filter-list 1 out
neighbor 150.50.100.5 <http://150.50.100.5/> remote-as 65256
neighbor 150.50.100.5 <http://150.50.100.5/> next-hop-self
neighbor 150.50.100.5 <http://150.50.100.5/> route-map 200Filter out
neighbor 200.0.0.1 <http://200.0.0.1/> remote-as 100
no auto-summary
R2(config-router)#neigh 200.0.0.1 <http://200.0.0.1/> ebgp-multihop 2
<<<Note the removal of the peer, and the appropriate deletion. Then it's
recreated with multihop 2>>>
R2(config-router)#do sh ip bgp sum
BGP router identifier 200.0.0.2 <http://200.0.0.2/> , local AS number 65256
BGP table version is 5, main routing table version 5
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
150.50.24.4 <http://150.50.24.4/> 4 300 0 0 0 0
0 never Active
150.50.100.5 <http://150.50.100.5/> 4 65256 0 0 0
0 0 never Active
200.0.0.1 <http://200.0.0.1/> 4 100 0 0 0 0
0 never Active
<<<Ready and waiting>>>
R2(config-router)#do deb ip pack det
IP packet debugging is on (detailed)
R2(config-router)#
*Jun 11 04:03:01.007: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), routed via FIB
*Jun 11 04:03:01.007: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 44, sending
*Jun 11 04:03:01.011: TCP src=34362, dst=179, seq=1444273798, ack=0,
win=16384 SYN
*Jun 11 04:03:01.015: IP: tableid=0, s=200.0.0.1 <http://200.0.0.1/>
(FastEthernet1/0), d=150.50.17.2 <http://150.50.17.2/> (FastEthernet1/0),
routed via RIB
*Jun 11 04:03:01.015: IP: s=200.0.0.1 <http://200.0.0.1/>
(FastEthernet1/0), d=150.50.17.2 <http://150.50.17.2/> (FastEthernet1/0),
len 44, rcvd 3
*Jun 11 04:03:01.015: TCP src=179, dst=34362, seq=2326681210,
ack=1444273799, win=16384 ACK SYN
*Jun 11 04:03:01.015: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), routed via FIB
*Jun 11 04:03:01.015: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 40, sending
*Jun 11 04:03:01.015: TCP src=34362, dst=179, seq=1444273799,
ack=2326681211, win=16384 ACK
*Jun 11 04:03:01.023: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEth
R2(config-routeernet1/0), routed via FIB
*Jun 11 04:03:01.023: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 85, sending
*Jun 11 04:03:01.023: TCP src=34362, dst=179, seq=1444273799,
ack=2326681211, win=16384 ACK PSH
*Jun 11 04:03:01.043: IP: s=200.0.0.1 <http://200.0.0.1/>
(FastEthernet1/0), d=150.50.17.2 <http://150.50.17.2/> , len 104, rcvd 0
*Jun 11 04:03:01.047: TCP src=179, dst=34362, seq=2326681211,
ack=1444273844, win=16339 ACK PSH
*Jun 11 04:03:01.051: %BGP-5-ADJCHANGE: neighbor 200.0.0.1
<http://200.0.0.1/> Up
*Jun 11 04:03:01.051: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), routed via FIB
*Jun 11 04:03:01.051: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 59, sending
*Jun 11 04:03:01.051: TCP src=34362, dst=179, seq=1444273844,
ack=2326681275, win=16320 ACK PSH
*Jun 11 04:03:01.059: IP: s=200.0.0.1 <http://200.0.0.1/>
(FastEthernet1/0), d=150.50.17.2 <http://150.50.17.2/> , len 108, rcvd 0
*Jun 11 04:03:01.059: TCP src=179, dst=34362, seq=2326681275,
ack=1444273863, win=16320 ACK PSH
*Jun 11 04:03:01.059: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), routed via FIB
*Jun 11 04:03:01.059: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 78, sending
*Jun 11 04:03:01.059: TCP src=34362, dst=179, seq=1444273863,
ack=2326681343, win=16252 ACK PSH
*Jun 11 04:03:01.071: IP: s=200.0.0.1 <http://200.0.0.1/>
(FastEthernet1/0), d=150.50.17.2 <http://150.50.17.2/> , len 78, rcvd 0
*Jun 11 04:03:01.071: TCP src=179, dst=34362, seq=2326681343,
ack=1444273901, win=16282 ACK PSH
*Jun 11 04:03:01.275: IP: tableid=0, s=150.50.17.2 <http://150.50.17.2/>
(local), d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), routed via FIB
*Jun 11 04:03:01.275: IP: s=150.50.17.2 <http://150.50.17.2/> (local),
d=200.0.0.1 <http://200.0.0.1/> (FastEthernet1/0), len 40, sending
*Jun 11 04:03:01.275: TCP src=34362, dst=179, seq=1444273901,
ack=2326681381, win=16214 ACKr)#
R2(config-router)#do sh ip bgp sum
BGP router identifier 200.0.0.2 <http://200.0.0.2/> , local AS number 65256
BGP table version is 7, main routing table version 7
2 network entries using 234 bytes of memory
2 path entries using 104 bytes of memory
2/1 BGP path/bestpath attribute entries using 248 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 610 total bytes of memory
BGP activity 4/2 prefixes, 4/2 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down
State/PfxRcd
150.50.24.4 <http://150.50.24.4/> 4 300 0 0 0 0
0 never Active
150.50.100.5 <http://150.50.100.5/> 4 65256 0 0 0
0 0 never Active
200.0.0.1 <http://200.0.0.1/> 4 100 5 4 7 0
0 00:00:10 2
R2(config-router)#do un all
All possible debugging has been turned off
R2(config-router)#
So we see the packets coming in sourced from 150.50.17.2
<http://150.50.17.2/> destined for the loopback interface. Multihop config
is 2 and it works!
If we were going to/from the loopback on R1, then that would add another
hop. But from one loopback to the other loopback may require that you have
another hop in there. :)
HTH,
Scott
_____
From: Carlos Valero [mailto:[EMAIL PROTECTED]
Sent: Tuesday, June 10, 2008 11:02 PM
To: 'OSL CCIE Routing and Switching Lab Exam'; [EMAIL PROTECTED]
Subject: Re: [OSL | CCIE_RS] EBGP Multihop
Hi,
I had forgotten to ask you a question about ebgp-multihop.
Since this issue was raised, this question came back to my mind.
This is about BGP Lab 7 (v9.0). I know you don't have v9.0 anymore, but
this should not be too complicated for you.
One of the initial tasks was to configure R1 on AS 100 and R2 on AS 200, but
peering with R1's loopback.
Of course we need to use ebgp-multihop in this case. But while I was
expecting to see "ebgp-multihop 2", the actual solution used "ebgp-multihop
3"
I tried "ebgp-multihop 2" just to see, but of course it did not work!
But I'm not sure why.
If they were peering using a Serial Link, then "ebgp-multihop 2" would be
OK; I know that.
But in this case R1 and R2 are connected through Switch 1 on VLAN 12.
Does the Switch count as an additional hop?
If that's the case, is it because the Switch is acting as Layer 3 device?
What if the switch was a pure Layer 2 device, with no VLAN?
Would I still need "ebgp-multihop 3" instead of "ebgp-multihop 2" ?
--- On Tue, 6/10/08, Scott Morris <[EMAIL PROTECTED]> wrote:
From: Scott Morris <[EMAIL PROTECTED]>
Subject: Re: [OSL | CCIE_RS] EBGP Multihop
To: "'OSL CCIE Routing and Switching Lab Exam'"
<[email protected]>
Date: Tuesday, June 10, 2008, 3:32 PM
It's mandatory to have reachability. :) However you choose to do that in
order to build your session is between you and your lab requirements!
But no reachability = no bgp session!
HTH,
Scott
_____
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Hari
Sent: Tuesday, June 10, 2008 3:01 PM
To: [email protected]
Subject: [OSL | CCIE_RS] EBGP Multihop
Hi all,
While configuring EBGP Multihop command in BGP , do we need to configure IGP
route or static route for that particular neighbor?
Is it mandatory to configure IGP route or static route ?
Thanks
Hari
_____
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