Mark,Good work. For the next

Mark Schwartz · ‎02-07-2015

Hello,

I have a small GNS3 lab that is working with one exception: I cannot ping loopback0 on RRc2 and RRc3 from RRc1.

RRc1, RRc2 and RRc3 can all ping loopback0 on SmileyISP and RRc2 and RRc3 can ping each others loopback0

interfaces.

I am broken between the two route-reflectors: RRS1 and RRS2.

Given these conditions:

1) Do not configure any IGP.

2) No static routes

How do I get connectivity from RRc1's loopback0 interface to RRc2 loopback0 and RRc3 loopback0?

I used a route-map to set the next hop, but I am obviously doing something wrong.

I am providing relevant show command outputs, router configs, and the GNS3 topology.net config.

You will have to change the image and working directories to match your computer.

Not quite sure where I am going wrong.

Any help would be greatly appreciated.

Thanks.

-- Mark

RRc1#sh ip bgp
BGP table version is 53, local router ID is 172.16.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
*>i 1.1.1.0/24       10.1.25.5                0    100      0 100 i
*>i 10.1.12.0/24     10.1.26.2                0    100      0 i
*>i 10.1.13.0/24     10.1.12.1                0    100      0 i
*>i 10.1.14.0/24     10.1.12.1                0    100      0 i
*>i 10.1.15.0/24     10.1.12.1                0    100      0 i
*>i 10.1.25.0/24     10.1.26.2                0    100      0 i
* i 10.1.26.0/24     10.1.26.2                0    100      0 i
*>                   0.0.0.0                  0         32768 i
*> 172.16.1.0/24    0.0.0.0                  0         32768 i
*>i 172.16.2.0/24    10.1.12.1                0    100      0 i
*>i 172.16.3.0/24    10.1.12.1                0    100      0 i
RRc1#

RRc1#ping 172.16.2.1 so lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.2.1, timeout is 2 seconds:
Packet sent with a source address of 172.16.1.1
.....
Success rate is 0 percent (0/5)
RRc1#

RRc2#sh ip bgp
BGP table version is 31, local router ID is 172.16.2.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
*>i 1.1.1.0/24       10.1.15.5                0    100      0 100 i
* i 10.1.12.0/24     10.1.12.2                0    100      0 i
* i 10.1.13.0/24     10.1.13.1                0    100      0 i
*>                   0.0.0.0                  0         32768 i
*>i 10.1.14.0/24     10.1.13.1                0    100      0 i
*>i 10.1.15.0/24     10.1.13.1                0    100      0 i
* i 10.1.25.0/24     10.1.12.2                0    100      0 i
* i 10.1.26.0/24     10.1.12.2                0    100      0 i
* i 172.16.1.0/24    10.1.12.2                0    100      0 i
*> 172.16.2.0/24    0.0.0.0                  0         32768 i
*>i 172.16.3.0/24    10.1.14.4                0    100      0 i
RRc2#

SmileyISP#sh run
Building configuration...

Current configuration : 988 bytes
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname SmileyISP
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.15.5 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
ip address 10.1.25.5 255.255.255.0
speed auto
duplex auto
!
router bgp 100
bgp log-neighbor-changes
network 1.1.1.0 mask 255.255.255.0
network 10.1.15.0 mask 255.255.255.0
neighbor 10.1.15.1 remote-as 200
neighbor 10.1.25.2 remote-as 200
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

RRS1#sh run
Building configuration...

Current configuration : 1594 bytes
!
! Last configuration change at 19:24:34 UTC Sat Feb 7 2015
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname RRS1
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.15.1 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
ip address 10.1.12.1 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet2/0
ip address 10.1.13.1 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet2/1
ip address 10.1.14.1 255.255.255.0
speed auto
duplex auto
!
router bgp 200
bgp log-neighbor-changes
network 10.1.13.0 mask 255.255.255.0
network 10.1.14.0 mask 255.255.255.0
network 10.1.15.0 mask 255.255.255.0
neighbor RouteReflectors peer-group
neighbor RouteReflectors remote-as 200
neighbor RouteReflectors route-map NEXTHOP out
neighbor RRClients peer-group
neighbor RRClients remote-as 200
neighbor RRClients route-reflector-client
neighbor 10.1.12.2 peer-group RouteReflectors
neighbor 10.1.13.3 peer-group RRClients
neighbor 10.1.14.4 peer-group RRClients
neighbor 10.1.15.5 remote-as 100
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
route-map NEXTHOP permit 10
set ip next-hop peer-address
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

RRS2#sh ru
Building configuration...

Current configuration : 1542 bytes
!
! Last configuration change at 19:42:06 UTC Sat Feb 7 2015
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname RRS2
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.12.2 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
ip address 10.1.25.2 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet2/0
ip address 10.1.26.2 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet2/1
no ip address
shutdown
speed auto
duplex auto
!
router bgp 200
bgp log-neighbor-changes
network 10.1.12.0 mask 255.255.255.0
network 10.1.25.0 mask 255.255.255.0
network 10.1.26.0 mask 255.255.255.0
neighbor RouteReflectors peer-group
neighbor RouteReflectors remote-as 200
neighbor RouteReflectors route-map NEXTHOP out
neighbor RRClients peer-group
neighbor RRClients remote-as 200
neighbor RRClients route-reflector-client
neighbor 10.1.12.1 peer-group RouteReflectors
neighbor 10.1.25.5 remote-as 100
neighbor 10.1.26.6 peer-group RRClients
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
route-map NEXTHOP permit 10
set ip next-hop peer-address
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

RRc1#sh run
Building configuration...

Current configuration : 1005 bytes
!
! Last configuration change at 18:43:57 UTC Sat Feb 7 2015
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname RRc1
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface Loopback0
ip address 172.16.1.1 255.255.255.0
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.26.6 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
router bgp 200
bgp log-neighbor-changes
network 10.1.26.0 mask 255.255.255.0
network 172.16.1.0 mask 255.255.255.0
neighbor 10.1.26.2 remote-as 200
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

RRc2#sh run
Building configuration...

Current configuration : 1005 bytes
!
! Last configuration change at 18:45:05 UTC Sat Feb 7 2015
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname RRc2
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface Loopback0
ip address 172.16.2.1 255.255.255.0
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.13.3 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
router bgp 200
bgp log-neighbor-changes
network 10.1.13.0 mask 255.255.255.0
network 172.16.2.0 mask 255.255.255.0
neighbor 10.1.13.1 remote-as 200
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

RRc3#wr term
Building configuration...

Current configuration : 1005 bytes
!
! Last configuration change at 18:31:12 UTC Sat Feb 7 2015
!
version 15.2
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname RRc3
!
boot-start-marker
boot-end-marker
!
no aaa new-model
!
ip cef
no ipv6 cef
!
multilink bundle-name authenticated
!
interface Loopback0
ip address 172.16.3.1 255.255.255.0
!
interface FastEthernet0/0
no ip address
shutdown
duplex half
!
interface FastEthernet1/0
ip address 10.1.14.4 255.255.255.0
speed auto
duplex auto
!
interface FastEthernet1/1
no ip address
shutdown
speed auto
duplex auto
!
router bgp 200
bgp log-neighbor-changes
network 10.1.14.0 mask 255.255.255.0
network 172.16.3.0 mask 255.255.255.0
neighbor 10.1.14.1 remote-as 200
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
control-plane
!
line con 0
logging synchronous
transport preferred none
stopbits 1
line aux 0
stopbits 1
line vty 0 4
login
!
end

autostart = False
version = 0.8.6
[127.0.0.1:7202]
    workingdir = C:\Users\Mark\AppData\Local\Temp
    udp = 10200
    [[7200]]
        image = C:\downloads\GNS3\c7200-adventerprisek9-mz.152-4.S5.image
        idlepc = 0x62f1e4ec
        ghostios = True
    [[ROUTER SmileyISP]]
        console = 2005
        aux = 2100
        cnfg = configs\SmileyISP.cfg
        slot1 = PA-2FE-TX
        f1/0 = RRS1 f1/0
        f1/1 = RRS2 f1/1
        x = -24.0
        y = -259.0
        z = 1.0
        hx = -1.5
        hy = -24.0
    [[ROUTER RRc1]]
        console = 2015
        aux = 2101
        cnfg = configs\RRc1.cfg
        slot1 = PA-2FE-TX
        f1/0 = RRS2 f2/0
        x = -292.0
        y = 200.0
        z = 1.0
        hx = -5.5
        hy = -25.0
[127.0.0.1:7200]
    workingdir = C:\Users\Mark\AppData\Local\Temp
    udp = 10000
    [[7200]]
        image = C:\downloads\GNS3\c7200-adventerprisek9-mz.152-4.S5.image
        idlepc = 0x62f1e4ec
        ghostios = True
    [[ROUTER RRS1]]
        console = 2012
        aux = 2102
        cnfg = configs\RRS1.cfg
        slot1 = PA-2FE-TX
        f1/0 = SmileyISP f1/0
        f1/1 = RRS2 f1/0
        slot2 = PA-2FE-TX
        f2/0 = RRc2 f1/0
        f2/1 = RRc3 f1/0
        x = 197.0
        y = 6.0
        z = 1.0
        hx = 42.5
        hy = -20.0
    [[ROUTER RRS2]]
        console = 2013
        aux = 2103
        cnfg = configs\RRS2.cfg
        slot1 = PA-2FE-TX
        f1/0 = RRS1 f1/1
        f1/1 = SmileyISP f1/1
        slot2 = PA-2FE-TX
        f2/0 = RRc1 f1/0
        x = -239.0
        y = 9.0
        z = 1.0
        hx = 1.5
        hy = -24.0
[127.0.0.1:7201]
    workingdir = C:\Users\Mark\AppData\Local\Temp
    udp = 10100
    [[7200]]
        image = C:\downloads\GNS3\c7200-adventerprisek9-mz.152-4.S5.image
        idlepc = 0x62f1e4ec
        ghostios = True
    [[ROUTER RRc3]]
        console = 2009
        aux = 2104
        cnfg = configs\RRc3.cfg
        slot1 = PA-2FE-TX
        f1/0 = RRS1 f2/1
        x = 337.0
        y = 155.0
        z = 1.0
        hx = 17.5
        hy = -25.0
    [[ROUTER RRc2]]
        console = 2008
        aux = 2105
        cnfg = configs\RRc2.cfg
        slot1 = PA-2FE-TX
        f1/0 = RRS1 f2/0
        x = 149.0
        y = 204.0
        z = 1.0
        hx = -13.5
        hy = -23.0
[GNS3-DATA]
    configs = configs
    [[NOTE 1]]
        text = ".1"
        x = 208.0
        y = -23.0
    [[NOTE 2]]
        text = "10.1.12.0/24"
        x = -19.0
        y = 5.0
    [[NOTE 3]]
        text = ".1"
        x = 153.0
        y = 25.0
    [[NOTE 4]]
        text = ".1"
        x = 259.0
        y = 33.0
    [[NOTE 5]]
        text = "10.1.13.0/24"
        x = 238.0
        y = 84.0
        rotate = 99
    [[NOTE 6]]
        text = "10.1.25.0/24"
        x = -188.0
        y = -124.0
    [[NOTE 7]]
        text = "l0: 172.16.2.1/24"
        x = 125.0
        y = 244.0
    [[NOTE 8]]
        text = "l0:172.16.1.1/24"
        x = -269.0
        y = 240.0
    [[NOTE 9]]
        text = "10.1.15.0/24"
        x = 116.0
        y = -127.0
    [[NOTE 10]]
        text = "10.1.14.0/24"
        x = 293.0
        y = 53.0
        rotate = 50
    [[NOTE 11]]
        text = ".1"
        x = 194.0
        y = 68.0
    [[NOTE 12]]
        text = "AS100"
        x = -20.0
        y = -342.0
    [[NOTE 13]]
        text = ".2"
        x = -148.0
        y = 46.0
    [[NOTE 14]]
        text = "AS200"
        x = 33.0
        y = 300.0
    [[NOTE 15]]
        text = "l0: 1.1.1.1/24"
        x = -42.0
        y = -306.0
    [[NOTE 16]]
        text = ".5"
        x = 50.0
        y = -213.0
    [[NOTE 17]]
        text = ".2"
        x = -248.0
        y = 60.0
    [[NOTE 18]]
        text = ".2"
        x = -174.0
        y = -52.0
    [[NOTE 19]]
        text = ".5"
        x = -54.0
        y = -209.0
    [[NOTE 20]]
        text = ".6"
        x = -232.0
        y = 189.0
    [[NOTE 21]]
        text = "l0:172.16.3.1/24"
        x = 299.0
        y = 194.0
    [[NOTE 22]]
        text = "10.1.26.0/24"
        x = -274.0
        y = 167.0
        rotate = 290
    [[NOTE 23]]
        text = ".3"
        x = 208.0
        y = 187.0
    [[NOTE 24]]
        text = ".4"
        x = 312.0
        y = 155.0
    [[SHAPE 1]]
        type = ellipse
        x = 50.0
        y = -35.0
        width = 385.0
        height = 345.0
        fill_color = "#ffff7f"
        border_style = 2
        z = -1.0
    [[SHAPE 2]]
        type = ellipse
        x = -171.0
        y = -346.0
        width = 359.0
        height = 200.0
        fill_color = "#aaff7f"
        border_style = 2
        z = -1.0
    [[SHAPE 3]]
        type = ellipse
        x = -407.0
        y = -87.0
        width = 883.0
        height = 443.0
        border_style = 2
        z = -2.0
    [[SHAPE 4]]
        type = ellipse
        x = -361.0
        y = -29.0
        width = 385.0
        height = 326.0
        fill_color = "#55aaff"
        border_style = 2
        z = -3.0

briadunn · ‎02-08-2015

Hello,

If the RR Client cant use a static or an IGP to reach the next-hop what other options are there. Can next-hop self be used here? Ask why or why not, with this topology. Try also moving your route-map down to the RR Client vs the RR. Look into how the RR Clients can reach the next-hop being advertised in the BGP prefix.

Thanks,

BD

Mark Schwartz · ‎02-08-2015

BD,

I actually found this lab here: https://www.m00nie.com/2010/09/bgp-route-reflectors-gns3-lab/

The solution posted by the author does not work (it even generates an error).

I have been trying to 'fix' it with no success. If you look at the site, the author does not

use an IGP (although he does say an IGP would fix the problem) or any static routes.

He shows how a route-map can be used (except his route map doesn't work).

It looks like it should be fixable with just BGP, but I am NOT a BGP guru by any stretch of the imagination.

briadunn · ‎02-08-2015

Mark,

In his config, he's setting a next-hop for the peering between the RR's. Your issue is reachability between Loopbacks on the RR clients. Remember that the RR's are just 'reflecting routes' they have received, to the RR clients.

So ask how RRc1 can reach the RRc2 Loopback, via the next-hop advertised in the prefix? This is where I mentioned previously some options to ask yourself - can using "neighbor next-hop self on the RR's, towards the RR clients, be used here? if yes, try it out. if no, ask why.

Next, try the route-map on the RR's, facing the RR clients and setting a next-hop. Does this work? if yes, why did it work and what next-hop did you specify?

Thanks,

BD

Mark Schwartz · ‎02-08-2015

BD,

Ahh...

OK. In the original article, the author states that the final piece with the route map

NEXTHOP was supposed to fix the reachability issue. Obviously it doesn't.

After reading your last post, I looked more carefully at the output from 'sh ip bgp'

on each of the client routers and I realized that several of the next hop addresses were

wrong for some of the prefixes.

1) I completely removed the 'neighbor RouteReflectors route-map NEXTHOP out'

from both RR's. Then I ran 'sh ip bgp' on the clients and noted a change in the next hop addresses. Still wrong, but it changed.

2) I then tried next-hop-self from the RR's to the clients, but it did not change from where

it was after I completed step 1. I am not sure why there was no change. (actually, see the very end of this post)

3) I then applied my version of the route map: route-map NEXTHOP permit 10
set ip next-hop peer-address

to the RR's with this: neighbor RRClients route-map NEXTHOP out

That fixed it. All three clients have as their next hop for all prefixes their respective

RR's (which is what they should have for this topology).

I have full connectivity everywhere, even loopback to loopback between all clients.

1) THANK YOU for pointing me in the right direction.

2) If I may ask, why did next hop self fail? More specifically, I saw no change at all

in the next hop for the advertised prefixes. Is it because next-hop-self should be used

for eBGP peers and all of the RR's and clients are all within the same AS?

briadunn · ‎02-08-2015

Mark,

Good work.

For the next-hop-self; yes you're right. Using this command on the RR will modify next hop attributes "only for prefixes that are learned from eBGP peers"... so not the prefixes that are being reflected from RRC's. Just wanted you to see this behavior during your troubleshooting.

Thanks

BD

BGP route-reflector next-hop issue