Dec 1 2008
Configuring Traffic Engineering using the explicit path-option
Lets start by configuring a dynamic tunnel between PE1 and PE2 using the tunnel configuration below.
interface Tunnel100
ip unnumbered Loopback0
tunnel destination 3.3.3.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng priority 5 5
tunnel mpls traffic-eng bandwidth 512
tunnel mpls traffic-eng path-option 1 dynamic
Now lets examine the path the tunnel takes.
PE1#show mpls traffic-eng tunnels tunnel 100
Name: PE1_t100 (Tunnel100) Destination: 3.3.3.3
Status:
Admin: up Oper: up Path: valid Signalling: connected
path option 1, type dynamic (Basis for Setup, path weight 20)
Config Parameters:
Bandwidth: 512 kbps (Global) Priority: 5 5 Affinity: 0x0/0xFFFF
Metric Type: TE (default)
AutoRoute: disabled LockDown: disabled Loadshare: 512 bw-based
auto-bw: disabled
InLabel : -
OutLabel : Serial1/1.1, 20
RSVP Signalling Info:
Src 1.1.1.1, Dst 3.3.3.3, Tun_Id 100, Tun_Instance 3
RSVP Path Info:
My Address: 10.0.0.1
Explicit Route: 10.0.0.2 10.0.0.6 3.3.3.3
Record Route: NONE
Tspec: ave rate=512 kbits, burst=1000 bytes, peak rate=512 kbits
RSVP Resv Info:
Record Route: NONE
Fspec: ave rate=512 kbits, burst=1000 bytes, peak rate=512 kbits
Shortest Unconstrained Path Info:
Path Weight: 20 (TE)
Explicit Route: 10.0.0.2 10.0.0.6 3.3.3.3
History:
Tunnel:
Time since created: 4 minutes, 50 seconds
Time since path change: 3 minutes, 53 seconds
Current LSP:
Uptime: 3 minutes, 53 seconds
Selection: reoptimation
Prior LSP:
ID: path option 1 [2]
Removal Trigger: configuration changed
PE1#
If you examine the Explicit Route you can see the actual path the tunnel takes(Due to the limited topology there is only one path the tunnel could take). If we want we can actually force the tunnel to take this path by defining an explicit path.
Defining an explicit path takes two steps.
Step 1 – Define the explicit-path ie the path the TE tunnel will take
PE1(config)#ip explicit-path name DEBUGALL enable
PE1(cfg-ip-expl-path)#
PE1(cfg-ip-expl-path)#next-address 10.0.0.2
Explicit Path name DEBUGALL:
1: next-address 10.0.0.2
PE1(cfg-ip-expl-path)#next-address 10.0.0.6
Explicit Path name DEBUGALL:
1: next-address 10.0.0.2
2: next-address 10.0.0.6
PE1(cfg-ip-expl-path)#next-address 3.3.3.3
Explicit Path name DEBUGALL:
1: next-address 10.0.0.2
2: next-address 10.0.0.6
3: next-address 3.3.3.3
PE1(cfg-ip-expl-path)#exit
Step 2 – attach the explicit path to the TE tunnel.
interface Tunnel100
tunnel mpls traffic-eng path-option 1 explicit name DEBUGALL
Verify the tunnel is up and using the explicit path.
PE1#show mpls traffic-eng tunnels tunnel 100
Name: PE1_t100 (Tunnel100) Destination: 3.3.3.3
Status:
Admin: up Oper: up Path: valid Signalling: connected
path option 1, type explicit DEBUGALL (Basis for Setup, path weight 20)
Looks good.
Jan 11, 2009 @ 03:30:42
Hi,
I also noticed that some of the configuration example, for explicit route, we can also put loopback of next-hop router, rather than next-hop ip address and loose keyword and the end of command line.
I wounder how different this would be on next-hop or maybe TE have a reason for it?
Thanks in advance.
maher
Nov 03, 2009 @ 14:03:39
Hi I would like to know how a tunnel is capable to identify when a traffic is voice or data. This is because I´m working with intserv but I don´t know how the router handle this process
Nov 04, 2009 @ 17:46:25
Hi David
I will be moving to TE later this year. I’ll address this point when I get there.
Zarar