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Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter11 SDH Topologies and Up grades
11.8 Four Node Configurations
11.8 Four Node Configurations
You can link multiple ONS 15454 SDHs using their STM-N cards (that is, create a fiber-optic bus) to
accommodate more access traffic than a single ONS 15454 SDH can support. Refer to the
CiscoONS 15454 SDH Procedure Guide for more information. You can link nodes with STM-4 or
STM-16 fiber spans as you would link any other two network nodes. The nodes can be grouped in one
facility to aggregate more local traffic. Each shelf assembly is recognized as a separate node in the
ONS 15454 SDH software interface and traffic is mapped using CTC cross-connect options.
11.9 STM-N Speed Upgrades
A span is the optical fiber connection between two ONS 15454 SDH nodes. In a span (optical speed)
upgrade, the transmission rate of a span is upgraded from a lower to a higher STM-N signal but all othe r
span configuration attributes remain unchanged. With multiple nodes, a span upgrade is a coordinated
series of upgrades on all nodes in the ring or protection group. You can perform in-service span upgrades
for the following ONS 15454 SDH cards:
•Single-port STM-4 to STM-16
•Single-port STM-4 to STM-64
•STM-16 to STM-64
You can also perform in-service card upgrades for the following ONS15454 cards:
•Four-port STM-1 to eight-port STM-1
•Single-port STM-4 to four-port STM-4
Note Since the four-port STM-1 to eight-port STM-1 cards and the single-port STM-4 to four-port STM-4
cards are the same speed, they are not considered span upgrades.
To perform a span upgrade, the higher-rate optical card must replace the lower-rate card in the same slot.
If the upgrade is conducted on spans residing in an MS-SPRing, all spans in the ring must be upgraded.
The protection configuration of the original lower-rate optical card (two-fiber MS-SPRing, four-fiber
MS-SPRing, SNCP ring, and 1+1) is retained for the higher-rate STM-N card.
When performing span upgrades on a large number of nodes, we recommend that you upgra de all spans
in a ring consecutively and in the same maintenance window. Until all spans are upgraded, mismatched
card types are present.
We recommend using the Span Upgrade Wizard to perform span upgrades. Although you can also use
the manual span upgrade procedures, the manual proc edures are mainly provided as error recovery for
the wizard. The Span Upgrade Wizard and the Manual Span Upgrade procedures require at least two
technicians (one at each end of the span) who can co mmunicate with each other during the upgrade.
Upgrading a span is non-service affecting and causes no more than three switches, each of which is less
than 50 ms in duration.
Note Span upgrades do not upgrade SDH topologies, for example, a 1+1 group to a two-fiber MS-SPRing.
Refer to the Cisco ONS 15454 SDH Procedure Guide for topology upgrade procedures.