06-24-2014 05:02 AM - edited 03-04-2019 11:13 PM
We are planning to replace 3560 running bgp with an ASR 1001. They are connected to a same switch which is then connected to our ISP.
My goal is to have them work independently.
I tried below configuration but 3560 stuck-in-active while the ASR routing table is populated with prefixes.
ASR
!
router bgp 54321
bgp router-id 1.2.3.5
bgp log-neighbor-changes
network 1.2.3.0 mask 255.255.248.0
neighbor 11.11.11.11 remote-as 55555
neighbor 11.11.11.11 transport path-mtu-discovery
neighbor 11.11.11.11 password 7 1231415151B1E5429203557
neighbor 11.11.11.11 update-source g0/0/0.3333
neighbor 11.11.11.11 soft-reconfiguration inbound
neighbor 22.22.22.22 remote-as 44444
neighbor 22.22.22.22 transport path-mtu-discovery
neighbor 22.22.22.22 update-source g0/0/0.7777
neighbor 22.22.22.22 soft-reconfiguration inbound
no auto-summary
!
3560
!
!
router bgp 54321
bgp router-id 1.2.3.4
bgp log-neighbor-changes
network 1.2.3.0 mask 255.255.248.0
neighbor 11.11.11.10 remote-as 55555
neighbor 11.11.11.10 transport path-mtu-discovery
neighbor 11.11.11.10 password 7 1231415151B1E5429203557
neighbor 11.11.11.10 update-source Vlan3333
neighbor 11.11.11.10 soft-reconfiguration inbound
neighbor 22.22.22.22 remote-as 44444
neighbor 22.22.22.22 transport path-mtu-discovery
neighbor 22.22.22.22 update-source Vlan7777
neighbor 22.22.22.22 soft-reconfiguration inbound
no auto-summary
!
Attached is the complete configuration.
Thanks,
Caren
Solved! Go to Solution.
06-24-2014 11:11 PM
Hi Caren ,
Expanding subnet mask should be done simultaneously at both side (ISP & Yourside) . Else you will loose existing connectivity.
When you expand subnet mask NID , BID everything get changes .
Normally ISP set /30 for all WAN connectivity .
HTH
Sandy
06-24-2014 05:29 AM
Hi ,
I do see your both switch & router is holding same IP address , this cause IP duplication in LAN segment .
You need expand your subnet mask on interface configuration . configure different IP address for switch & ASR1001
You should see %IP-4-DUPADDR: message on your log message .
switch :
interface Vlan 3333 description ISP Link 1 ip address 11.11.11.9 255.255.255.252 ! interface Vlan7777 description ISP Link 2 ip address 22.22.22.21 255.255.255.252
Router :
interface GigabitEthernet0/0/0.3333 description ISP LINK1 encapsulation dot1Q 3333 ip address 11.11.11.9 255.255.255.252 ! interface GigabitEthernet0/0/0.7777 description ISP LINK2 encapsulation dot1Q 7777 ip address 22.22.22.21 255.255.255.252
HTH
Sandy
06-24-2014 11:05 PM
Hi Sandy,
You're right, I saw an IP address duplication message yesterday during deployment.
Just a noob question, if the ISP configure their subnet mask in /30 and share the IP with switch. If setup the router /29 most probably, router will be denied by ISP. Am I right? I guess and I hope, the ISP do not set it to /30.
I will give it a try this afternoon.
Thanks,
Caren
06-24-2014 11:11 PM
Hi Caren ,
Expanding subnet mask should be done simultaneously at both side (ISP & Yourside) . Else you will loose existing connectivity.
When you expand subnet mask NID , BID everything get changes .
Normally ISP set /30 for all WAN connectivity .
HTH
Sandy
06-25-2014 01:55 AM
Hello Sandy,
Thanks for the explanation.
I feel I am stuck here. Working with my ISP is a huge task and need more time to get their attention (my manager is rushing me to finish this off). Do I have any other option here like iBGP or any other workaround?
Thanks,
Caren
06-25-2014 05:00 AM
As i said earlier run one BGP session from ASR1001 & one BGP session from your 3560 . Internally between your 3560 & ASR1001 run IGP (OSPF /EIGRP) .
HTH
Sandy
06-26-2014 12:00 AM
Hi Sandy,
Thanks for the response. I'll fire up my gns3 and make some test.
Regards,
Caren
07-03-2014 05:00 AM
Hi Sandy.
Thank you for those ideas. My ASR is now working. I replaced the switch with ASR directly, got only 20 minutes downtime.
Regards,
Caren
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