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Cisco ONS 15454 Reference Manual, R8.5.x
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Chapter 11 Circuits and Tunnels
11.23.1 Server Trail Protection Types
11.23.1 Server Trail Protection Types
The server trail protection type determines the protection type for any circuits that traverse it. A server
trail link can be one of the following protection types:
• Preemptible—PCA circuits will use server trails with the Preemptible attribute.
• Unprotected—In Unprotected Server Trail, CTC assumes that the circuits going out from that
specific port will not be protected by provider network and will look for a secondary path from
source to destination if you are creating a protected circuit.
• Fully Protected—In Fully Protected Server Trail, CTC assumes that the circuits going out from that
specific port will be protected by provider network and will not look for a secondary path from
source to destination.
Note Only path protection is available on server trails. BLSR protection is not available on server trail.
11.23.2 VCAT Circuit Routing over Server Trails
An STS-3c server trail can be used to route STS-3c circuits and an STS-1 server trail can be used to route
STS-1 circuits. Similarly, a VT1.5 server trail can be used to route VT1.5 circuits and an STS-12c server
trail can only be used for STS-12c circuits.
For example, to route a STS-3c-2v circuit over a server trail, you must enable split fiber routing and
create two STS-3c server trails and route each member manually or automatically over each server trail.
To route a STS-12c-2v circuit over a server trail, you must enable split fiber routing and create two
STS-12c server trails and route each member manually or automatically over each server trail.
Note Server trails can only be created between any two optical ports or EC-1 ports.
VCAT circusits can be created over server trails in the following ways:
• Manual routing
• Automatic routing
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Diverse routing: This method enables VCAT circuit routing over diverse server trail links.
Note When creating circuits or VCATs, you can choose a server trail link during manual circ uit routing. CTC
may also route circuits over server trail links during automatic routing. VCAT common-fiber automatic
routing is not supported.
For a detailed procedure on how to route a VCAT circuit over a server trail, refer “Chapter 6, Create
Circuits and VT Tunnels, Section NTP-A264, Create an Automatically Routed VCAT Circuit and
Section NTP-A265, Create a Manually Routed VCAT Circuit” in the Cisco ONS 15454 Procedure
Guide.