Policy-Based Tunnel Selection - Cisco NCS 5500 Series Configuration Manuals

Implementing UCMP
via 200.0.0.1/32, tunnel-te3, 3 dependencies, weight 1, class 0 [flags 0x0]
via 200.0.0.1/32, tunnel-te4, 3 dependencies, weight 1, class 0 [flags 0x0]
via 200.0.0.1/32, tunnel-te5, 3 dependencies, weight 1, class 0 [flags 0x0]

Policy-Based Tunnel Selection

Policy-Based Tunnel Selection (PBTS) provides a mechanism that lets you direct traffic into specific TE
tunnels based on different criteria.
PBTS is a special case in UCMP calculation. It uses load share command to configure weight. The UCMP
algorithm normalizes each class independently and it uses max_path from PD specific max_tunnels_per_class,
which is 64 for ASR9K. UCMP with PBTS can have more total_paths (buckets) than the supported number
of paths (buckets) for all Forwarding Classes (FCs), which is 64 for ASR9K.
All other XR platform sets 8 buckets per FC and 64 buckets for all 8 (0-7) FCs. After normalization, the total
number buckets do not exceed platform limit.
Example
The show cef ipv6 command displays the PBTS class information in the following output.
Router# show cef ipv6 97:: detail
97::/64, version 88177, internal 0x1000001 0x0 (ptr 0x980eef7c) [1], 0x0 (0x974366b8), 0xa28
(0x988842c0)
Updated Mar
Prefix Len 64, traffic index 0, precedence n/a, priority 2
gateway array (0x97e54770) reference count 11, flags 0x28, source rib (7), 0 backups
LW-LDI[type=1, refc=1, ptr=0x974366b8, sh-ldi=0x9799a3f8]
gateway array update type-time 4 Mar
LDI Update time Mar
LW-LDI-TS Mar
via ::ffff:200.0.0.1/128, tunnel-te45, 3 dependencies, weight 1, forward class 6 [flags
0x0]
next hop 200.0.0.1/32
local adjacency
path-idx 2 NHID 0x0 [0x7244d544 0x0]
next hop 200.0.0.1/32
local adjacency
path-idx 3 NHID 0x0 [0x7244d694 0x0]
next hop 200.0.0.1/32
local adjacency
path-idx 4 NHID 0x0 [0x7244d7e4 0x0]
next hop 200.0.0.1/32
local adjacency
Weight distribution:
slot 0, weight 8, normalized_weight 8, class 0
slot 1, weight 4, normalized_weight 4, class 0
slot 2, weight 1, normalized_weight 1, class 0
slot 3, weight 1, normalized_weight 1, class 0
slot 4, weight 1, normalized_weight 1, class 0
7 05:44:46.875
[12 type 1 flags 0x200401 (0x9799a3f8) ext 0x0 (0x0)]
7 05:46:11.118
7 05:46:11.118
path-idx 0 NHID 0x0 [0x97b51978 0x0]
next hop VRF - 'default', table - 0xe0000000
Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.3.x
7 05:46:11.118
Policy-Based Tunnel Selection
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