Vt Tunnels; Figure 6-12 Example #4: Two Vt1.5 Circuits In Upsr Or 1+1 Protection Scheme - Cisco ONS 15327 User Documentation

Cross-Connect Card Capacities

Figure 6-12 Example #4: Two VT1.5 circuits in UPSR or 1+1 protection scheme

VT1.5 circuit #1
Source
DS-1
VT1.5 circuit #2
Unless you create VT tunnels (see the
the XTC VT matrix at each node through which the circuit passes.
•
•

6.8.2 VT Tunnels

To maximize VT matrix resources, you can tunnel VT1.5 circuits through ONS 15327 pass-through
nodes (nodes that are not a circuit source or drop). VT1.5 tunnels provide two benefits:
•
•
Figure 6-13
tunnel, which can carry 28 VT1.5s. However, the tunnel does use two STS matrix ports on each node
through which it passes.
Cisco ONS 15327 User Documentation, R3.3
6-18
XTC Matrices
STS Matrix
6 STSs total used
18 STSs available
VT1.5 Matrix
Two STSs are used at each node in the
the Figure 6-11 example.
In the Figure 6-10 example, three STSs are used at the source and drop nodes and four STSs are used
at pass-through nodes. In Figure
STSs at the pass-through nodes.
They allow you to route VT1.5 circuits through ONS 15454s that have XC cards. (VT1.5 circuits
require XCVT or XC10G cards at circuit source and drop nodes.)
When tunneled through nodes, VT1.5 tunnels do not use VT matrix capacity, thereby freeing the VT
matrix resources for other VT1.5 circuits.
shows a VT tunnel through the XTC matrices. No VT1.5-mapped STSs are used by the
Circuit #1 (working)
Circuit #2 (working)
OC-12
Circuit #1 (protect)
Circuit #2 (protect)
OC-12
STS
VT1.5
"VT Tunnels" section on page
Figure 6-9 example, and three STSs are used at each node in
6-12, six STSs are used at the source and drop nodes and four
Chapter 6 Circuits and Tunnels
Drop
Drop
6-18), VT1.5 circuits use STSs on
June 2002