how to check type of LDP in 7750

[mike18]

Hi Everyone,

Which command I can run on 7750 to see type of LDP configured?

Regards
Mike

[Stoffen]

You can run the "show router ldp session" and see if the LDP peer is link, targeted or both.

[mike18]

IT shows it is targeted

[Stoffen]

Here is an example.
Topology is R1 <-> R2 <-> R4

Code: Select all

*A:SR04# show router ldp session 

==============================================================================
LDP IPv4 Sessions
==============================================================================
Peer LDP Id         Adj Type  State         Msg Sent  Msg Recv  Up Time
------------------------------------------------------------------------------
10.0.0.1:0          Targeted  Established   7         8         0d 00:00:04
10.0.0.2:0          Link      Established   18        20        0d 00:00:20
------------------------------------------------------------------------------
No. of IPv4 Sessions: 2
==============================================================================

R4 has LINK LDP adjacency type towards R2 and Targeted towards R1.

R4 only has 1 interface configured for LDP

Code: Select all

*A:SR04# show router ldp interface     

===============================================================================
LDP Interfaces
===============================================================================
Interface                         Adm/Opr                            
 Sub-Interface(s)                  Adm/Opr  Hello Hold  KA    KA    Transport
                                            Fctr  Time  Fctr  Time  Address
-------------------------------------------------------------------------------
to_SR02                           Up/Up                             
  ipv4                              Up/Up   3     15    3     30    System
-------------------------------------------------------------------------------
No. of Interfaces: 1
===============================================================================

The Targeted session is established due to the use of a MPLS based SDP between R1 and R4.
Signalling of MPLS SDP's use targeted ldp, and you can see that in the output below, Sig TLDP.

Link LDP is only needed for directly connected peers, but they can be link and targeted, type BOTH.

Code: Select all

*A:SR04# show service sdp 

============================================================================
Services: Service Destination Points
============================================================================
SdpId  AdmMTU  OprMTU  Far End          Adm  Opr         Del     LSP   Sig
----------------------------------------------------------------------------
401    0       8682    10.0.0.1         Up   Up          MPLS    L     TLDP
----------------------------------------------------------------------------
Number of SDPs : 1
----------------------------------------------------------------------------

You can read more about LDP here: https://infoproducts.alcatel-lucent.com ... Intro.html

[mike18]

When i run show router ldp session i see the 30 targetted sessions but when i run

show router ldp interface

===============================================================================
LDP Interfaces
===============================================================================
Interface Adm Opr Hello Hold KA KA Transport
Factor Time Factor Timeout Address
-------------------------------------------------------------------------------
No Matching Entries Found
===============================================================================


does this mean that we are not using LDP at all ?
we are only using the LSP between directly connected nei and far end device right?

[mivens]

I would have thought that means you have targeted LDP sessions only (no link LDP).

Maybe take a look at "show router tunnel-table" - it will show you the different LSPs it's using for transport.

[mike18]

show router tunnel-table

===============================================================================
Tunnel Table (Router: Base)
===============================================================================
Destination Owner Encap TunnelId Pref Nexthop Metric
-------------------------------------------------------------------------------
10.0.20.38/32 sdp MPLS 38 5 10.0.20.38 0
10.0.20.38/32 rsvp MPLS 22 7 10.0.9.62 1100
10.0.20.39/32 sdp MPLS 39 5 10.0.20.39 0
10.0.20.39/32 rsvp MPLS 23 7 10.0.9.62 1200
10.0.20.40/32 sdp MPLS 40 5 10.0.20.40 0
10.0.20.40/32 rsvp MPLS 65 7 10.0.9.62 200
10.0.20.41/32 sdp MPLS 41 5 10.0.20.41 0
10.0.20.41/32 rsvp MPLS 64 7 10.0.180.245 212
10.0.20.44/32 sdp MPLS 44 5 10.0.20.44 0
10.0.20.44/32 rsvp MPLS 41 7 10.0.180.250 1212
10.0.20.46/32 sdp MPLS 46 5 10.0.20.46 0
10.0.20.46/32 rsvp MPLS 49 7 10.0.180.245 1112
10.0.20.48/32 sdp MPLS 48 5 10.0.20.48 0
10.0.20.48/32 rsvp MPLS 46 7 10.0.180.250 1012
10.0.20.49/32 sdp MPLS 49 5 10.0.20.49 0
10.0.20.49/32 rsvp MPLS 44 7 10.0.180.245 1012
10.0.20.51/32 sdp MPLS 51 5 10.0.20.51 0
10.0.20.51/32 rsvp MPLS 48 7 10.0.180.250 112
10.0.20.52/32 sdp MPLS 52 5 10.0.20.52 0
10.0.20.52/32 rsvp MPLS 47 7 10.0.9.2 100
10.0.20.56/32 sdp MPLS 56 5 10.0.20.56 0
10.0.20.56/32 rsvp MPLS 61 7 10.0.9.2 1100
10.0.20.58/32 sdp MPLS 58 5 10.0.20.58 0
10.0.20.58/32 rsvp MPLS 66 7 10.0.180.250 1012

so do we use LSP ? please confirm what we use

[mivens]

LSP is short for "Label Switched Path".
Which label to use for that LSP can be signaled by LDP, RSVP etc.

In your case, it's via RSVP.

For example, there is a targeted LDP session with 10.0.20.38/32 and to transport the traffic to 10.0.20.38/32 an RSVP signalled MPLS-TE tunnel is used. I.e.10.0.9.62 has used RSVP to say which label to use so that if it is sent a packet, it will be forwarded over an LSP to 10.0.20.38/32.

So a service using SDP 38 to get to 10.0.20.38/32 would have two labels imposed, the transport label signalled by the RSVP session and a service label signalled by the targeted LDP session.