Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Hub-and-Spoke topology VPN problem

hi, everyone,

i setuped a mpls/vpn network with hub-and-spoke topology, and use OSPF as the routing protocol between ce and pes, here's the problem:

spoke routes import into hub-ce router very well, but when they comeback from another hub-ce interface to PE, there're LSA information in the database, but they can not injected into PE's VRF routing table, and i can find debug information as below:

02:31:25: OSPF: Start processing Summary LSA 75.75.75.75, mask 255.255.255.255, adv 192.168.0.2, age 154, seq 0x80000005 (Area 0)

02:31:25: OSPF: Downward bit set/Non-backbone LSA

02:31:25: OSPF: Start processing Summary LSA 192.168.0.4, mask 255.255.255.252, adv 192.168.0.2, age 154, seq 0x80000005 (Area 0)

02:31:25: OSPF: Downward bit set/Non-backbone LSA

02:31:25: OSPF: sum_delete_old_routes area 0

02:31:25: OSPF: Started Building Type 5 External Routes

and the show ip ospf database show that these LSA have no routing bit set as the normal one, does anybody can figure out what's wrong? or any workaround? many thanks.

R11#sh ip ospf da summary 75.75.75.75

OSPF Router with ID (192.168.0.14) (Process ID 100)

Summary Net Link States (Area 0)

LS age: 602

Options: (No TOS-capability, DC, Downward)

LS Type: Summary Links(Network)

Link State ID: 75.75.75.75 (summary Network Number)

Advertising Router: 192.168.0.2

LS Seq Number: 80000006

Checksum: 0x6CB0

Length: 28

Network Mask: /32

TOS: 0 Metric: 2

R11#

2 REPLIES
New Member

Re: Hub-and-Spoke topology VPN problem

hi, everyone,

i have search a internet draft to describe this situation, "Using an LSA Options Bit to Prevent Looping in BGP/MPLS IP VPNs", from "http://www.ietf.org/internet-drafts/draft-ietf-ospf-2547-dnbit-03.txt"

does anyone can tell me how can disable this function and clear the "DN" bit on a cisco router? thanks very much.

New Member

Re: Hub-and-Spoke topology VPN problem

hi, everyone,

i maybe found the workaround, i config these command in PE's vrf ospf process:

router ospf 100 vrf aaa

domain-id 192.168.0.2

domain-tag 500

i think this workarond works, but could anyone tell me how this whole thing dealed by the cisco router? and is it kind of change the default domain-id and domain-tag to make router igrone the "DN" bit?

thanks for help.

225
Views
0
Helpful
2
Replies
CreatePlease to create content