Operation Manual – MPLS TE
H3C S9500 Series Routing Switches
Chapter 1 MPLS TE Configuration
1-21
To do…
Use command to…
Remarks
Configure the wide metric
attribute of IS-IS
cost-style
{
narrow
|
wide
|
wide-compatible
|
{
compatible
|
narrow-compatible
}
[
relax-spf-limit
] }
Required
By default, IS-IS uses
narrow metric style.
Enable IS-IS TE
traffic-eng
[
level-1
|
level-2
|
level-1-2
]
Required
Disabled by default
Note:
With the S9500 series, if you enable IS-IS TE on an interface configured with both
primary and secondary IP addresses, IS-IS TE advertises only the primary IP address
of the interface in the LSP’s IS reachability TLV (type 22).
V. Configuring an MPLS TE explicit path
An explicit path is a set of nodes. The relationship between any two neighboring nodes
on an explicit path can be either of the following:
z
Strict: where the two nodes are directly connected.
z
Loose: where the two nodes have devices in between.
When inserting nodes to an explicit path or modifying nodes on it, you may configure
the
include
keyword to have the established LSP traverse the specified nodes or the
exclude
keyword to have the established LSP bypass the specified nodes.
Caution:
z
According to RFC 3784, the length of the IS reachability TLV (type 22) may reach
the maximum of 255 octets in some cases.
z
For an IS-IS LSP to carry this type of TLV and to be flooded normally on all
interfaces with IS-IS enabled, the MTU of any IS-IS enabled interface, including 27
octets of LSP header and two octets of TLV header, cannot be less than 284 octets.
If an LSP must also carry the authentication information, the minimum MTU needs
to be recalculated according to the packet structure.
In a word, with the TE feature, the MTU of any interface with IS-IS enabled is
recommended to be equal to or greater than 512 octets to guarantee that IS-IS LSPs
can be flooded on the network.
Follow these steps to configure an MPLS TE explicit path:
