Shared Resource Link Group; Traffic Routing Over A Third-Party Network; Vt Traffic Routing Over An Ons 15600 Hub Node - Cisco ONS 15600 Reference Manual

7.17 Traffic Routing over a Third-Party Network

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.

7.16.2.1 Shared Resource Link Group

The Shared Resource Link Group (SRLG) attribute can be assigned to a server trail link using a
commonly shared resource such as port, fiber or span. For example, if two server trail links are routed
over the same fiber, an SRLG attribute can be assigned to these links. SRLG is used by Cisco Transport
Manager (CTM) to specify link diversity. If you create multiple server trails from one port, you can
assign the same SRLG value to all the links to indicate that they originate from the same port.
7.17 Traffic Routing over a Third-Party Network
If ONS 15600s are connected to a third-party network, you can create an open-ended Path Protection
circuit to route a circuit through it. To do this, you create three STS circuits. One circuit is created on
the source ONS 15600 network. This circuit has one source and two destinations, one at each ONS 15600
that is connected to the third-party network. The second circuit is created on the third-party network so
that the circuit travels across the network on two paths to the ONS 15600s. That circuit routes the two
circuit signals across the network to ONS 15600s that are connected to the network on other side. At the
destination node network, the third circuit is created with two sources, one at each node connected to the
third-party network. A selector at the destination node chooses between the two signals that arrive at the
node, similar to a regular Path Protection circuit.

7.18 VT Traffic Routing over an ONS 15600 Hub Node

When an ONS 15600 node is configured as a hub between compatible protection domains, it is possible
to use CTC to automatically create circuits, including VT circuits from an ONS 15454 node, across the
domains. VT circuits cannot terminate on an ONS 15600 node. All combinations of protection domains
are compatible for STS circuits, including combinations of Path Protection and line-protected domains.
When you must route VT traffic over an ONS 15600 hub node connecting Path Protection,
line-protected, and unprotected domains, you must manually create the circuits for this traffic. For
specific information on ONS 15454 VT circuit creation and tunneling, refer to the Cisco ONS 15454
Procedure Guide
Figure 7-14
network, an ONS 15454 BLSR network, and a 1+1 protected ONS 15454 node.
Cisco ONS 15600 Reference Manual, R8.0
7-28
shows an ONS 15600 as a protection domain hub between a ONS 15454 Path Protection
Chapter 7 Circuits and Tunnels