H3C Technologies H3C S10500 Series Switches - Manual (Page 129)

118
Configuring the FRR polling timer
The protection provided by FRR is temporary. Once a protected LSP becomes available again or a new
LSP is established, traffic is switched to the protected or new LSP. After this switchover, the PLR polls
available bypass tunnels for the best one at the regular interval specified by the FRR polling timer:
Follow these steps to configure the FRR polling timer:
To do… Use the command... Remarks
Enter system view of the PLR node system-view ––
Enter MPLS view mpls ––
Configure the FRR polling timer
mpls te timer fast-reroute
[ seconds ]
Optional
The FRR polling timer is 300
seconds by default.
Inspecting an MPLS TE tunnel
On an MPLS TE network, when an MPLS TE tunnel fails, the control plane cannot detect the failure or
cannot do so in time. This brings difficulty to network maintenance. To detect MPLS TE tunnel failures in
time and locate the failed node, the device provides the following mechanisms:
• MPLS LSP ping
• MPLS LSP tracert
• BFD for an MPLS TE tunnel
• Periodic tracert of an MPLS TE tunnel
MPLS LSP ping
MPLS LSP ping can be used to check the connectivity of an MPLS TE tunnel. At the ingress, it adds the
label of the tunnel into an MPLS echo request, and sends it along the MPLS TE tunnel to the egress. The
ingress determines whether the MPLS TE tunnel is normal according to whether it can receive a reply from
the egress.
Use the following command to check the connectivity of an MPLS TE tunnel:
To do… Use the command… Remarks
Use MPLS LSP
ping to check the
connectivity of an
MPLS TE tunnel
ping lsp [ -a source-ip | -c count | -exp exp-value | -h
ttl-value | -m wait-time | -r reply-mode | -s
packet-size | -t time-out | -v ] * te interface-type
interface-number
Required
Available in any view
MPLS LSP tracert
MPLS LSP tracert can be used to locate errors of an MPLS TE tunnel. It sends MPLS echo requests to the
nodes along the MPLS TE tunnel to be inspected, with the TTL increasing from 1 to a specified value. Each
node along the MPLS TE tunnel will return an MPLS echo reply to the ingress due to TTL timeout. Thus, the
ingress can collect the information of each hop along the MPLS TE tunnel, so as to locate the failed node.
You can also use MPLS LSP tracert to collect important information of each hop along the MPLS TE tunnel,
such as the label allocated.
Use the following command to locate errors of an MPLS TE tunnel: