Flex Lsp Phase 2 - Cisco ASR 900 Series Manual

Flex LSP Phase 2

RSVP Signalling Info:
Shortest Unconstrained Path Info:
Reason for the tunnel being down: Bidirectional: standby error from [4.4.4.4][UNK] LSP[8]
History:
Flex LSP Phase 2
Flex LSP phase 2 is supported effective Cisco IOS XE Everest 16.5.1. Flex LSP also known as Associated
Bidirectional Label Switched Paths (LSPs) are LSP instances where the forward and the reverse direction
paths are set up, monitored, protected independently, and associated together during signaling. The RSVP
Association aims to bind the forward and reverse LSPs together to form either a co-routed or a non co-routed
associated bidirectional traffic engineering (TE) tunnel.
The Cisco IOS XE Everest 16.5.1 supports only co-routed Flex LSP tunnels. Flex LSP Phase 2 supports the
following features:
• Shared Risk Link Groups (SRLGs) Protection – SRLGs indicate situations where links in a network
• Non-revertive
• Sticky
• Hop count and Cost max limit – Each path from the tunnel source node (head-end) to destination node
• ECMP min-fill, max-fill – Path calculation selects a path with the lowest accumulated path cost.
MPLS Basic Configuration Guide, Cisco IOS XE Everest 16.5.1 (Cisco ASR 900 Series)
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Src 4.4.4.4, Dst 1.1.1.1, Tun_Id 1001, Tun_Instance 9
RSVP Path Info:
My Address: 23.1.1.1
Explicit Route: 23.1.1.2 23.1.1.2* 10.1.1.1* 1.1.1.1*
Record Route:
Tspec: ave rate=200 kbits, burst=1000 bytes, peak rate=200 kbits
RSVP Resv Info:
Record Route: 10.1.1.2 10.1.1.1
Fspec: ave rate=200 kbits, burst=1000 bytes, peak rate=200 kbits
Path Weight: 2 (TE)
Explicit Route: 20.1.1.2 11.1.1.1 1.1.1.1
Tunnel:
Time since created: 8 minutes, 9 seconds
Time since path change: 6 minutes, 10 seconds
Number of LSP IDs (Tun_Instances) used: 9
Current LSP: [ID: 9]
Uptime: 6 minutes, 10 seconds
share a common fiber (or a common physical attribute). If one link fails, the other links in the group
may also fail. Links in this group have a shared risk.
The MPLS-TE SRLG Protection feature enhances backup tunnel path selection so that a backup tunnel
avoids using links that are in the same SRLG as interfaces the backup tunnel is protecting.
(tail-end) has a number of characteristics, including node hop count and accumulated path cost. Node
hop count is the number of nodes along a path excluding the source node.
To ensure that the ensure the selected path does not exceed the specified hop count, configure a maximum
node hop count.
Each link segment along the path has an associated path cost. Accumulated path cost is the sum of the
path cost of all link segments. In the co-routed tunnel case, the accumulated path cost includes both, the
forward and reverse link cost. To ensure the selected path does not exceed the specified cost value,
configure a cost max limit.
Sometimes there are multiple paths from the tunnel source node to the destination node, and all these
paths may have the same accumulated (and lowest) path cost. These paths are referred to as "Equal Cost
Flex LSP Overview