Server Trail Protection Types; Vcat Circuit Routing Over Server Trails - Cisco ONS 15600 Reference Manual

Chapter 7 Circuits and Tunnels
The server trail link is bidirectional and can be VT1.5, VT2, STS1, STS-3c, STS-6c, STS-12c, STS-48c,
or STS-192c; you cannot change an existing server trail to another size. It must be deleted and recreated.
A circuit provisioned over a server trail must match the type and size of the server trail it uses. For
example, an STS-3c server trail can carry only STS-3c circuits and not three STS-1 circuits.
There is no OSPF or any other management information exchange between NEs over a server trail.
Note

7.16.1 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:
•
•
•
Note Only path protection is available on server trails. BLSR procection is not available on server trail.

7.16.2 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:
•
•
When creating circuits or VCATs, you can choose a server trail link during manual circuit routing. CTC
Note
may also route circuits over server trail links during automatic routing. VCAT common-fiber automatic
routing is not supported.
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.
Manual routing
Automatic routing
Diverse routing: This method enables VCAT circuit routing over diverse server trail links.
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7.16.1 Server Trail Protection Types
Cisco ONS 15600 Reference Manual, R8.0
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