New to BGP, looking for help!

tmccolgan · ‎05-17-2015

I am brandy new to BGP (as of this weekend). I have a client that I am helping migrate from p2p T1s to Verizon MPLS. They have one HQ and (3) remote sites that all hone back to HQ (currenty with the p2p T1s).

I learned a lot about BGP when I received the configurations from them and I have since setup the the MFR interfaces, and sub-interface, BGP config with neighbors, AS etc.

My question is, what routing do I put in place to route the internal networks (192.168.0.0) across the WAN? Currently as the p2p config is setup, they run all static routing, so each remote location has an ip route to the p2p interface IP (10.255.255.x). How do I move the traffic to the MPLS network and eventually take out the p2p links?

My first attempt on one of the smaller locations was to move the default route and add a new one to the local MFR interface, but that did not work for me.

Any help would be appreciated thank you!

Tim

vivek srivastava · ‎05-17-2015

If you are using BGP as WAN routing protocol. Its simple.

e.g.

If you have local subnet of any site1 - 192.168.1.0/24

and If you have local subnet of any site2 - 192.168.2.0/24

On site1 router:

Router bgp xx

no sync

no auto

neighbor a.a.a.a remote-as <Verizon ASN>

neighbor a.a.a.a ebgp-multihop 2 !if applicable

neighbor a.a.a.a allowas-in

network 192.168.1.0 mask 255.255.255.0

On site2 router:

Router bgp xx

no sync

no auto

neighbor b.b.b.b remote-as <Verizon ASN>

neighbor b.b.b.b ebgp-multihop 2 !if applicable

neighbor b.b.b.b allowas-in

network 192.168.2.0 mask 255.255.255.0

tmccolgan · ‎05-18-2015

I've attempted this before, but could have been missing something.

My next question is, what would then be the default route for the router? Currently it is pointing to the local serial interface IP address, but this is for the old serial p2p link. With the new MPLS setup, what do I set the default gateway to? The MFR interface? The bgp neighbor IP address?

Richard Burts · ‎05-18-2015

Typically the default gateway would be the bgp neighbor IP address.

HTH

Rick

HTH

Rick

tmccolgan · ‎05-18-2015

I have attempted this as well, with no success, but again maybe I am missing something somewhere else.

Also, how does my provider know how to route my internal networks through their MPLS? Am I missing something with that?

vivek srivastava · ‎05-18-2015

Can you pls share the network diagram and below details:

sh run

sh ip bgp sum

sh ip bgp

sh ip route

tmccolgan · ‎05-18-2015

This is from one of the remote branch sites. As of right now the default gateway is pointing to the p2p interface IP address (for the old links which I want to move to the new MPLS)

sh ip bgp sum:

BGP router identifier 192.168.8.254, local AS number 65001
BGP table version is 5, main routing table version 5
2 network entries using 296 bytes of memory
2 path entries using 128 bytes of memory
2/2 BGP path/bestpath attribute entries using 272 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 720 total bytes of memory
BGP activity 3/1 prefixes, 3/1 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
65.x.x.37 4 65000 104 113 5 0 0 00:49:05 1

sh ip bgp neighbors:
BGP neighbor is 65.x.x.37, remote AS 65000, external link
BGP version 4, remote router ID 65.x.x.37
BGP state = Established, up for 00:51:39
Last read 00:00:24, last write 00:00:29, hold time is 90, keepalive interval is 30 seconds

sh ip bgp
BGP table version is 5, local router ID is 192.168.8.254
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
r> 65.x.x.36/30 65.x.x.37 0 65000 i
*> 192.168.8.0 0.0.0.0 0 32768 i

sh ip route:
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override

Gateway of last resort is 10.255.255.14 to network 0.0.0.0 old p2p t1 gateway moving away from this

S* 0.0.0.0/0 [1/0] via 10.255.255.14
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 10.255.255.12/30 is directly connected, Serial0/0/0
L 10.255.255.13/32 is directly connected, Serial0/0/0
65.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 65.x.x.36/30 is directly connected, MFR1.100
L 65.x.1.38/32 is directly connected, MFR1.100
192.168.8.0/24 is variably subnetted, 2 subnets, 2 masks
C 192.168.8.0/24 is directly connected, GigabitEthernet0/0
L 192.168.8.254/32 is directly connected, GigabitEthernet0/0

vivek srivastava · ‎05-18-2015

May be i'm a bit confused without a diagram but, If you running BGP as WAN routing protocol then static route (default router) is not required. I can see that you are receiving prefixes from the BGP already. You need to check what you have allowed under BGP network command, it should be only local routes which you want to send to other sites.

tmccolgan · ‎05-18-2015

This is the bgp from that specific site.

So I would just remove the 'ip route 0.0.0.0 0.0.0.0' entry from the config?

interface MFR1
description Verizon MPLS c0050392-66056286-5589261
no ip address
encapsulation frame-relay IETF
!
interface MFR1.100 point-to-point
ip address 65.x.x.38 255.255.255.252
frame-relay interface-dlci 100 IETF
!
interface GigabitEthernet0/0
description Inside
ip address 192.168.8.254 255.255.255.0
ip virtual-reassembly in
duplex auto
speed auto
!
interface Serial0/2/0:0
no ip address
encapsulation frame-relay MFR1
no arp frame-relay
!
interface Serial0/2/1:0
no ip address
encapsulation frame-relay MFR1
no arp frame-relay
!
router bgp 65001
bgp log-neighbor-changes
network 192.168.8.0
neighbor 65.x.x.37 remote-as 65000

vivek srivastava · ‎05-18-2015

config looks ok as far as you use class-c subnet. What about the HQ site ??

what it shows in "sh ip bgp" at both remote site and HQ??

tmccolgan · ‎05-18-2015

HQ bgp config:

router bgp 65001
bgp log-neighbor-changes
network 192.168.2.0
neighbor 65.x.x.21 remote-as 65000 (verizon)

sh ip bgp
BGP table version is 54, local router ID is 192.168.2.253
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
r> 65.x.x.20/30 65.x.x.21 0 65000 i
*> 192.168.2.0 0.0.0.0 0 32768 i

vivek srivastava · ‎05-18-2015

Try with below config and share the results of the last two commands on both routers:

HQ bgp config:

router bgp 65001
bgp log-neighbor-changes
network 192.168.2.0 mask 255.255.255.0
neighbor 65.x.x.21 remote-as 65000
neighbor 65.x.x.21 disable-connected-check
neighbor 65.x.x.21 allowas-in
no sync
no auto
end
!
clear ip bgp *
!after 5 min.
# sho ip bgp summ
# sh ip bgp

--------------------------------------------------------
Remote Site bgp config:

!
router bgp 65001
bgp log-neighbor-changes
network 192.168.8.0 mask 255.255.255.0
neighbor 65.x.x.37 remote-as 65000
neighbor 65.x.x.37 disable-connected-check
neighbor 65.x.x.37 allowas-in
no sync
no auto
end
!
clear ip bgp *
!after 5 min.
# sho ip bgp summ
# sh ip bgp

tmccolgan · ‎05-18-2015

I am doing this now. I guess I also want to understand what I want to see in the bgp show commands to see that the internal networks are communicating? Would be old p2p t1 links get in the way of all this?

Jon Marshall · ‎05-18-2015

When you do a "sh ip bgp" you want to see all the remote subnets and they should also be in the IP routing table.

If you are using a default route with the other link then it should not interfere because you will be receiving more specific routes via BGP and your router should use those.

Jon

tmccolgan · ‎05-18-2015

Another forum suggested that I ask the carrier to check their PE and that they are accepting routes for each side and sending it across the network. I have a message out the VZ engineer asking this.