The MPLS-OPS Archive

Cell Relay Retreat>MPLS-OPS Archive>month:2005-May> msg00012



[Date Prev][Date Next][Thread Prev][Thread Next]  
  [Date Index][Thread Index][Author Index][Subject Index]

maximum number of labels pushed on Cisco GSR

  • From: "Li, Ling" <lili@ciena.com>
  • Date: Thu, 12 May 2005 09:51:35 -0400
  • Resent-Date: Thu, 12 May 2005 09:52:16 -0400
  • X-OriginalArrivalTime: 12 May 2005 13:51:54.0105 (UTC) FILETIME=[C15FBE90:01C556F9]
  • X-Scanned-By: MIMEDefang 2.45

Title:

Hi,

Read the following from Cisco VPN document.

If TE tunnel is protected by FRR and FRR is triggered by a link failure on PE1, PE1 needs to

push the following 4 labels to carry VPN traffic from CE1 to CE2:

1. Backup Tunnel Label
2. Primary Tunnel Label
3. TDP/LDP Label
4. VPN label
 
Could anyone confirm that Cisco GSR support 4 Label pushes?
 
Thanks,
 
Ling
====================

http://cisco.com/en/US/tech/tk436/tk428/technologies_tech_note09186a0080125b01.shtml#intro

Case 2: VPN over a TE Tunnel When the TE Tunnel Is from PE1 to P2

Topology

mplsvpnte-3.gif 

Explanation

The solution to this problem is to enable TDP/LDP on the TE tunnel and to make it a tag-switched interface. In the example shown in the Solution, TDP is enabled on the Tunnel0 of PE1. P2 is configured for accepting directed hellos and forming directed TDP neighbors. So, PE1 receives the label for 10.11.11.11 from P2 via LDP. Now that Tunnel0 has been made a tag-switched interface and TDP has been enabled for the traffic to 10.11.11.11, PE1 uses both the labels; it uses the RSVP label to reach the TE tailend and the TDP label to reach 10.11.11.11.

In this scenario, PE1 uses the label stack {L2 L3 L1} to forward data to CE2 if these items are true:

  • L1 is the VPN label.

  • L2 is the RSVP label to reach the TE tailend.

  • L3 is the TDP label to reach 10.11.11.11 (received from P2).