Cisco ONS 15327, Пользовательская документация

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Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 6 Circuits and Tunnels
Cross-Connect Card Capacities
•
Auto —Assumes that the first string received from the drop port is the baseline string. An alarm is
raised when a string that differs from the baseline is received.
• Manual —Uses the Current Expected String field as the baseline string. An alarm is raised when a
string that differs from the Current Expected String is received.
Step 16
Click Apply and click Close .
After you set up the path trace, the received string is displayed in the Received box on the path trace
setup window (
Figure 6-8 ). Click Switch Mode to toggle between ASCII and hexadecimal display. Click
the Reset button to reread values from the port. Click Default to return to the path trace default settings
(Path Trace Mode is set to Off and the New Transmit and New Expected Strings are null).
6.8 Cross-Connect Card Capacities
The ONS 15327 XTC cards perform port-to-port time-division multiplexing (TDM) at the STS-1 and
VT 1.5 levels.
XTC cards have the capacity to terminate 288 STSs, or 144 STS cross-connections (each STS
cross-connection uses two STS ports on the cross-connect card STS matrix).
6.8.1 VT1.5 Cross-Connects
The XTC card can map up to 24 STSs for VT1.5 traffic. Because one STS can carry 28 VT1.5s, the XTC
card can terminate up to 672 VT1.5s, or 336 VT1.5 cross-connects. However, to terminate 336 VT1.5
cross-connects:
•
Each STS mapped for VT1.5 traffic must carry 28 VT1.5 circuits. If you assign each VT1.5 circuit
to a different STS, the XTC VT1.5 cross-connect capacity will be reached after you create 12 VT1.5
circuits.
• ONS 15327s must be in a bidirectional line switched ring (BLSR). Source and drop nodes in UPSR
or 1+1 (linear) protection have capacity for only 224 VT1.5 cross-connects because an additional
STS is used for the protect path.
Figure 6-9 shows the logical flow of a VT1.5 circuit through the XTC card STS and VT matrices at a
BLSR node. The circuit source is a DS-1 port using STS-1. After the circuit is created:
• Two of the 24 XTC STSs available for VT1.5 traffic are used (one STS for VT1.5 input into the VT
matrix; one STS for VT1.5 output).
•
22 STSs are available for VT1.5 circuits.
•
The STS-1 from the DS-1 port has capacity for 27 more VT1.5 circuits.