11-27
Cisco ONS 15454 Reference Manual, R8.5.x
78-18106-01
Chapter 11 Circuits and Tunnels
11.15 Automatic Circuit Routing
11.15 Automatic Circuit Routing
If you select automatic routing during circuit creation, CTC routes the circuit by dividing the enti re
circuit route into segments based on protection domains. For unprotected segments of circuits
provisioned as fully protected, CTC finds an alternate route to protect the segment, crea ting a virtual path
protection configuration. Each segment of a circuit path is a separa te protection domain. Each protection
domain is protected in a specific protection scheme including card protecti on (1+1, 1:1, etc.) or SONET
topology (path protection, BLSR, etc.).
The following list provides principles and characteristics of automatic circuit routing:
• Circuit routing tries to use the shortest path within the user-specified or network-specified
constraints. VT tunnels are preferable for VT circuits because VT tunnels are considered shortcuts
when CTC calculates a circuit path in path-protected mesh networks.
• If you do not choose Fully Path Protected during circuit creation, circuits can st ill contain protected
segments. Because circuit routing always selects the shortest path, one or more links and/or
segments can have some protection. CTC does not look at link protection while computing a path
for unprotected circuits.
0xEA STS-1 with 10 VTx PDs
0xEB STS-1 with 11 VTx PDs
0xEC STS-1 with 12 VTx PDs
0xED STS-1 with 13 VTx PDs
0xEE STS-1 with 14 VTx PDs
0xEF STS-1 with 15 VTx PDs
0xF0 STS-1 with 16 VTx PDs
0xF1 STS-1 with 17 VTx PDs
0xF2 STS-1 with 18 VTx PDs
0xF3 STS-1 with 19 VTx PDs
0xF4 STS-1 with 20 VTx PDs
0xF5 STS-1 with 21 VTx PDs
0xF6 STS-1 with 22 VTx PDs
0xF7 STS-1 with 23 VTx PDs
0xF8 STS-1 with 24 VTx PDs
0xF9 STS-1 with 25 VTx PDs
0xFA STS-1 with 26 VTx PDs
0xFB STS-1 with 27 VTx PDs
0xFC VT-structured STS-1 SPE with 28 VT1.5
(Payload defects or a non-VT-structured STS-1 or STS-Nc SPE with a payload
defect.)
0xFF Reserved
Table 11-11 STS Path Signal Label Assignments for Signals with Payload Defects (continued)
Hex Code Content of the STS SPE