Configuring Distribution Trees - HP 6125XLG Configuration Manual

Step
6. Enter Ethernet or
aggregate interface
view.
7. Configure the minimum
LSP interval and the
maximum number of
LSPs transmitted per
time.

Configuring distribution trees

In a TRILL network, RBs compute distribution trees according to the LSDB, and use the distribution trees to
guide the forwarding of multicast, broadcast, and unknown unicast frames. An RB with a higher priority
is selected as the root bridge of a distribution tree.
An LSP carries distribution tree information that includes the number of distribution trees that the RB wants
all RBs to compute, the maximum number of distribution trees that the RB can compute (this number is
fixed at 15), and the number of distribution trees that the RB has computed.
An RB determines the number of distribution trees to compute (n) as follows: select the lower value
between the number of distribution trees that the highest-priority RB wants all RBs to compute and the
smallest value of the maximum number of distribution trees that each RB can compute. From the nickname
list in the LSP advertised by the RB with the highest priority, the first n nicknames comprise the root bridge
list that the local RB uses to compute distribution trees.
TRILL selects distribution trees for forwarding multicast, broadcast, and unknown unicast frames based on
the VLANs that the frames belong to. Because the topologies of TRILL distribution trees are different, traffic
can be load-shared. However, equal-cost links are not used for load-sharing.
When N equal-cost links exist in the network, each TRILL distribution tree selects the link with the largest
pseudo node ID for forwarding packets. As shown in
and RB 3. Assume the link directly connecting RB 1 to RB 3 has the largest pseudo node ID. Both the TRILL
distribution tree rooted at RB 3 and the TRILL distribution tree rooted at RB 4 select the link.
Figure 6 Multicast ECMP
RB 1
TRILL distribution trees support Equal Cost Multiple Path (ECMP), also known as multicast ECMP. When
multicast ECMP is enabled, TRILL assigns equal-cost links to different TRILL distributions trees. This
improves the load sharing performance.
Command
interface interface-type
interface-number
trill timer lsp interval [ count
count ]
RB 2
Cost = 1
Remarks
N/A
By default, the minimum LSP interval is 10
milliseconds, and the maximum number of
LSPs transmitted per time is 5.
Figure 6, two equal-cost links exist between RB 1
RB 3
10
RB 4