JUNOS MPLS LDP
Table of Contents
Introduction
This page discusses enabling MPLS LDP on a Junos device.
JUNOS MPLS LDP
- For LDP to operated on an interface, MPLS family has to be enabled on the logical interface.
- LDP installs LSPs only when both LDP and the (IGP) routing protocol are enabled. Without it, LDP won't bring up the session.
- LDP support Basic Discovery and Extended Discovery. Basic, connects to directly connected LDP neighbors, while extended uses targeted hellos.
- LDP Message Types:
- Discovery - Discovering neighbors (basic and extended.
- Session - Session being established via TCP.
- Advertising - FEC advertising.
- Notification - Error Notification and Advisory Notification. Error resets session, while advisory just a notification.
- By default LDP sends Hello message every 5 second for basic discovery (link hello) and 15 seconds for targeted discovery (targeted hello msg).
- Hello timer and Hello Hold timer is negotiated between LDP peers, where the lowest value wins. These timers are part of the discovery phase.
- Changing Hello hold timer values requires LDP session restart to allow peers to renegotiate (clear ldp sessions)
- LDP-signaled LSPs have a preference of 9 vs RSVP-signaled LSPs of 7 (see http://www.juniper.net/techpubs/en_US/junos13.3/topics/reference/general/routing-protocols-default-route-preference-values.html for details). Preference is like Administrative Distance in Cisco.
Relevant Commands
family mpls
set interfaces ae5 unit 0 family inet address 5.5.5.228/31
set interfaces ae5 unit 0 family mpls
protocol ldp interface
- Can be enabled individually or for all interfaces running MPLS and IGP.
set protocol ldp interface ae5.0
set protocol ldp interface all
protocol ldp interface ae6.0 disable
- Disables LDP per interface.
set protocol ldp interface ae6.0 disable
protocols ldp interface hello-interval
set protocols ldp interface (int) hello-interval 5
protocols ldp targeted-hello hello-interval
set protocols ldp targeted-hello hello-interval 10
protocols ldp targeted-hello hold-time
set protocols ldp targeted-hello hold-time (value)
protocols ldp interface hold-time
set protocols ldp interface (int) hold-time (value)
Command
{master}[edit ]
root@R1#