Default routing problem in E-bgp

suhailpuri · ‎10-19-2012

We have two data centers one in america D1 and another in europe D2 , both data center wan links are connected to mpls

the wan router of each data center has a wan link with ebgp session towards mpls and another interface connecting to internet router , so if there is intranet traffic then it goes over mpls and internet traffic goes to internet router at each data center

both routers have default route pointing towards EBGP neighbor , the problem is that if the servers in europe need to access internet then the traffic instead of going through internet router in europe goes through mpls into america datacentre and then america internet router and not utilizing the local internet router in europe

The IGP in both locations is EIGRP and EGP is EBGP

can some one help with this ?

Giuseppe Larosa · ‎10-19-2012

Hello Suhail,

my guess is that the Europe based WAN router is receiving a default route on the MPLS WAN link.

You can check the status of Europe WAN router with

show ip route 0.0.0.0

show ip bgp 0.0.0.0

It is likely that you will find two eBGP advertisements for net 0.0.0.0/0 with the one to the MPLS router preferred (may be for a higher local preference or other BGP attribute).

If so, all you need to do is to make the other default router preferred for example using a route-map applied inbound to european upstream provider to make it better ( for example increasing the local preference)

ip prefix-list ONLY-DEFAULT permit 0.0.0.0/0

route-map RISE-LP permit 10

match ip address prefix ONLY-DEFAULT

set local-preference 2000

route-map RISE-LP permit 20

router bgp

neigh x.x.x.x route-map RISE-LP in

where x.x.x.x is the eBGP peer with european upstream provider.

Note:

if you are receiving full internet table from both US and Europe the matter is different and can be solved by increasing the local preference for ALL routes received by the EU upstream provider.

Hope to help

Giuseppe

suhailpuri · ‎10-19-2012

thank you but i am a bit lost here i only see 1 entry for Ebgp advertisement

EDCNWR01#sh ip route 0.0.0.0

Routing entry for 0.0.0.0/0, supernet

Known via "eigrp 729", distance 170, metric 256512, candidate default path, type external

Redistributing via eigrp 729, bgp 10201

Advertised by bgp 10201 route-map EIGRP_to_BGP

Last update from 10.200.1.45 on GigabitEthernet0/0, 2d20h ago

Routing Descriptor Blocks:

* 10.200.1.45, from 10.200.1.45, 2d20h ago, via GigabitEthernet0/0

Route metric is 256512, traffic share count is 1

Total delay is 20 microseconds, minimum bandwidth is 10000 Kbit

Reliability 255/255, minimum MTU 1500 bytes

Loading 14/255, Hops 1

EDCNWR01#sh ip bgp 0.0.0.0

BGP routing table entry for 0.0.0.0/0, version 2

Paths: (1 available, best #1, table Default-IP-Routing-Table)

Advertised to update-groups:

1

Local

10.200.1.45 from 0.0.0.0 (10.200.248.5)

Origin IGP, metric 256512, localpref 100, weight 32768, valid, sourced, local, best

EDCNWR01#sh int gig 0/0

GigabitEthernet0/0 is up, line protocol is up

Hardware is BCM1125 Internal MAC, address is 0016.9dae.6290 (bia 0016.9dae.6290)

Description: EDCNCS01 G1/0/19

Internet address is 10.200.1.46/30

MTU 1500 bytes, BW 100000 Kbit/sec, DLY 10 usec,

reliability 255/255, txload 50/255, rxload 13/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s, media type is RJ45

output flow-control is XON, input flow-control is XON

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:01, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

30 second input rate 5219000 bits/sec, 2771 packets/sec

30 second output rate 19978000 bits/sec, 5963 packets/sec

3827870597 packets input, 3519855868 bytes, 0 no buffer

Received 972089 broadcasts, 0 runts, 0 giants, 0 throttles

5 input errors, 0 CRC, 0 frame, 5 overrun, 0 ignored

0 watchdog, 1315440 multicast, 0 pause input

0 input packets with dribble condition detected

2428111976 packets output, 1523567793 bytes, 0 underruns

2 output errors, 0 collisions, 1 interface resets

0 unknown protocol drops

0 babbles, 0 late collision, 0 deferred

2 lost carrier, 0 no carrier, 0 pause output

0 output buffer failures, 0 output buffers swapped out

EDCNWR01#sh int desc

Interface Status Protocol Description

Gi0/0 up up EDCNCS01 G1/0/19

Gi0/1 up up EDCNCS02 G1/0/20

Fa0/0/0 up up

Fa0/0/0.2 up up Verizon MPLS VPN: HexionSpecialtyChem; Site-Circuit: oude-meer-nld_w0w89730-1929016

Fa0/0/1 up down

Se1/0 admin down down Sprint PL# 499948 E3# 68181915 KPN V205276

Lo0 up up

EDCNWR01#sh ip bgp summ

BGP router identifier 10.200.248.5, local AS number 10201

BGP table version is 139068, main routing table version 139068

978 network entries using 117360 bytes of memory

983 path entries using 51116 bytes of memory

102/100 BGP path/bestpath attribute entries using 12648 bytes of memory

91 BGP AS-PATH entries using 2232 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

Bitfield cache entries: current 2 (at peak 2) using 60 bytes of memory

BGP using 183416 total bytes of memory

BGP activity 11888/10910 prefixes, 69370/68387 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd

68.139.83.65 4 65000 163918 58577 139067 0 0 2w5d 849

EDCNWR01#

Ajay Raj · ‎02-12-2013

Hi, Please share Topology Diagram with interface details and BGP config...

Alessio Andreoli · ‎02-12-2013

Check import and export policy.. Maybe the European data centre has not a valid membership for the Internet VRF ..

Hth
Alessio

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