Cisco Juniper MPLS Integration Problem.

[tckoon]

Hi,

I had problem to integrate the Cisco router to the Juniper MPLS core network.

Cisco router is PE and Juniper M20 is P/PE router. The LDP is running fine between both routers, but the only problem faced is Cisco PE router do not receive "tag/label" from the Juniper router. Please refer to below capture.

Any advice what to check/verify when connecting Cisco and Juniper together in MPLS network.

16 Untagged 211.24.210.28/30 0 Gi0/1 211.24.210.169

17 Untagged 211.24.210.72/30 0 Gi0/1 211.24.210.169

18 Untagged 211.24.210.180/30 0 Gi0/1 211.24.210.169

19 Untagged 211.24.210.32/30 0 Gi0/1 211.24.210.169

20 Untagged 211.24.210.176/30 0 Gi0/1 211.24.210.169

21 Untagged 211.24.210.16/30 0 Gi0/1 211.24.210.169

22 Untagged 211.24.210.128/30 0 Gi0/1 211.24.210.169

23 Untagged 211.24.210.40/30 0 Gi0/1 211.24.210.169

24 Untagged 203.121.20.0/27 0 Gi0/1 211.24.210.169

25 Untagged 211.24.210.56/30 0 Gi0/1 211.24.210.169

26 Untagged 211.24.210.48/30 0 Gi0/1 211.24.210.169

27 Untagged 211.24.210.80/30 0 Gi0/1 211.24.210.169

28 Untagged 211.24.210.152/30 0 Gi0/1 211.24.210.169

29 Untagged 211.24.210.136/30 0 Gi0/1 211.24.210.169

30 Untagged 211.24.210.112/30 0 Gi0/1 211.24.210.169

31 Untagged 211.24.210.120/30 0 Gi0/1 211.24.210.169

32 Untagged 211.24.210.88/30 0 Gi0/1 211.24.210.169

33 Untagged 211.24.210.144/30 0 Gi0/1 211.24.210.169

34 Untagged 211.24.210.96/30 0 Gi0/1 211.24.210.169

35 Untagged 211.24.210.104/30 0 Gi0/1 211.24.210.169

36 Untagged 211.24.210.160/30 0 Gi0/1 211.24.210.169

glsfb4-mbone#sh mpls ldp bind

glsfb4-mbone#sh mpls ldp bindings

tib entry: 0.0.0.0/0, rev 740

local binding: tag: imp-null

tib entry: 10.10.11.0/25, rev 742

local binding: tag: 383

tib entry: 10.10.11.128/25, rev 172

local binding: tag: 99

tib entry: 10.10.12.0/25, rev 744

local binding: tag: 384

tib entry: 10.10.12.128/25, rev 746

local binding: tag: 385

tib entry: 10.10.13.0/25, rev 748

local binding: tag: 386

tib entry: 10.10.13.128/25, rev 750

local binding: tag: 387

tib entry: 10.100.1.0/24, rev 174

local binding: tag: 100

tib entry: 10.250.254.0/27, rev 752

local binding: tag: 388

tib entry: 10.250.254.1/32, rev 176

local binding: tag: 101

tib entry: 10.250.254.2/32, rev 178

local binding: tag: 102

tib entry: 10.250.254.3/32, rev 180

glsfb4-mbone#sh mpls ldp discovery all

Local LDP Identifier:

10.254.250.14:0

Discovery Sources:

Interfaces:

GigabitEthernet0/1 (ldp): xmit/recv

LDP Id: 10.254.250.17:0

glsfb4-mbone#sh mpls ldp neighbor

Peer LDP Ident: 10.254.250.17:0; Local LDP Ident 10.254.250.14:0

TCP connection: 10.254.250.17.2353 - 10.254.250.14.646

State: Oper; Msgs sent/rcvd: 843/370; Downstream

Up time: 01:00:53

LDP discovery sources:

GigabitEthernet0/1, Src IP addr: 211.24.210.169

Addresses bound to peer LDP Ident:

211.24.210.169

[Harold Ritter]

It appears thet the M20 is not sending any label in our direction. Are you by any chance filtering labels on the M20.

Hope this helps,

[mheusinger]

Hi,

check, if there is an outbount LDP filter in the Juniper router:

LDP { export }

This could explain the described behaviour.

Regards, Martin

[tckoon]

I am not sure, attached the Juniper config.

Thanks

[oldcreek12]

By default, JUNOS LDP only advertises /32 loopback prefix-FEC bindings upstream, you need to explicitly configure egress policy under LDP to advertise other prefix-FEC mappings.

Side qeustion, why do we need the label mapping for other prefixes except loopbacks anyway? what application will need that?

[Harold Ritter]

Jian,

I agree with you that advertising labels for loopback interface addresses is preferable in most cases. You can use "tag-switching advertise-tags" command on the IOS side to only allow loopback interface addresses to propagate.

Hope this helps,

[tckoon]

Hi all, sorry for late reply.

Basically the VPN routes is sucessful advertised. The only problem is the next-hop ip (loopback) learn is not tag.

I can extended ping from 172.16.1.10 to 172.16.1.15 , but I cannot ping from 172.16.1.10 to 172.16.1 as the next hop is 10.254.250.16, which is not tag/label.

10.254.250.17 is LDP neighbor router loopback which is " POP-Tag".

glsfb4-mbone#sh ip ro vrf TEST

Routing Table: TEST

Codes: 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

Gateway of last resort is not set

172.16.0.0/32 is subnetted, 3 subnets

C 172.16.1.10 is directly connected, Loopback9930

B 172.16.1.5 [200/0] via 10.254.250.17, 01:04:16

B 172.16.1.1 [200/0] via 10.254.250.16, 01:04:16

37 Untagged 10.254.250.1/32 0 Gi0/1 211.24.210.169

38 Untagged 10.254.250.2/32 0 Gi0/1 211.24.210.169

39 Untagged 10.254.250.3/32 0 Gi0/1 211.24.210.169

40 Untagged 10.254.250.4/32 0 Gi0/1 211.24.210.169

41 Untagged 10.254.250.5/32 0 Gi0/1 211.24.210.169

42 Untagged 10.254.250.6/32 0 Gi0/1 211.24.210.169

43 Untagged 10.254.250.7/32 0 Gi0/1 211.24.210.169

44 Untagged 10.254.250.8/32 0 Gi0/1 211.24.210.169

45 Untagged 10.254.250.9/32 0 Gi0/1 211.24.210.169

46 Untagged 10.254.250.10/32 0 Gi0/1 211.24.210.169

47 Untagged 10.254.250.11/32 0 Gi0/1 211.24.210.169

48 Untagged 10.254.250.12/32 0 Gi0/1 211.24.210.169

49 Untagged 10.254.250.13/32 0 Gi0/1 211.24.210.169

50 Untagged 10.254.250.15/32 0 Gi0/1 211.24.210.169

51 Untagged 10.254.250.16/32 0 Gi0/1 211.24.210.169

52 Pop tag 10.254.250.17/32 0 Gi0/1 211.24.210.169

53 Untagged 10.254.250.254/32 0 Gi0/1 211.24.210.169

[tckoon]

attached is the diagram for your view.

[Harold Ritter]

Did you make the change I recommended on glsfb3 to include all the interfaces under the LDP process as follow:

protocols ldp {

interface all;

}

JunOS will not announce a label for a given prefix (FEC) unless it has already received a label for that same prefix. So glbp3 basically needs to receive a label for 10.254.250.16/32 from GLM-1 before it can advertise it to glbp4.

Hope this helps,

[tckoon]

Not yet as the Juniper router is in production network and is under customer care. I need to advice him to do the change , but it may take time as they need to know is the change can cause any downtime to the network.

Will update it once the change take place.

Many thanks

[Harold Ritter]

Note that you do receive a "implicit null" label for 10.254.250.17/32 (glbp3), which confirms that LDP is working properly between glbp3 and glbp4.

I notice that you are not using LDP in the core but RSVP instead. You could tunnel LDP over your MPLS TE tunnels by adding the ldp-tunneling command under each label-switch-path stanza as follow:

protocols {

mpls {

label-switched-path xxx {

from source;

to destination;

ldp-tunneling;

}

}

}

Note that this will have to be done at both end.

Hope this helps,

[Ali Norouzi]

Hi

jiangu I had same issue and by using your comment the problem resolved.

My desired application is MPLS forwarding. I want to forward all the traffic with MPLS lable.

Thank you,