6-18
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 6 Circuits and Tunnels
Cross-Connect Card Capacities
Figure 6-12 Example #4: Two VT1.5 circuits in UPSR or 1+1 protection scheme
Unless you create VT tunnels (see the
“VT Tunnels” section on page 6-18
), VT1.5 circuits use STSs on
the XTC VT matrix at each node through which the circuit passes.
•
Two STSs are used at each node in the
example, and three STSs are used at each node in
the
example.
•
In the
example, three STSs are used at the source and drop nodes and four STSs are used
at pass-through nodes. In
, six STSs are used at the source and drop nodes and four
STSs at the pass-through nodes.
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:
•
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
tunnel, which can carry 28 VT1.5s. However, the tunnel does use two STS matrix ports on each node
through which it passes.
STS Matrix
Circuit #1 (working)
XTC Matrices
DS-1
Source
6 STSs total used
18 STSs available
Circuit #2 (working)
Circuit #1 (protect)
Circuit #2 (protect)
STS
VT1.5
VT1.5 Matrix
OC-12
OC-12
VT1.5 circuit #1
VT1.5 circuit #2
Drop
Drop
71760
Summary of Contents for ONS 15327
Page 22: ...Contents xxii Cisco ONS 15327 User Documentation June 2002 I N D E X ...
Page 30: ...Figures xxviii Cisco ONS 15327 User Documentation June 2002 ...
Page 44: ...Procedures xlii Cisco ONS 15454 Installation and Operations Guide R3 2 June 2002 ...
Page 540: ...Glossary GL 16 Cisco ONS 15327 User Documentation R3 3 June 2002 ...
