Additional Routing Features In Mgx And Ses Nodes; Preferred Routing - Cisco Network Router User Manual

Chapter 4 Planning Intermediate Route Selection
Table 4-3 Link Selection Parameters Required for Various Classes of Service
Service
Class Address
CBR Required
rt-VBR Required
nrt-VBR Required
ABR Required
UBR
Required
1. CLR is the cell loss ratio for cells with the Cell Loss Priority bit set to 0.
0
2. CLR is the cell loss ratio for all cells with the Cell Loss Priority bit set to either 0 or 1.
0+1
When two parallel links are available along the route, the controller chooses a link based on the
configuration of the switch. The link selection options are:
•
•
•
•

Additional Routing Features in MGX and SES Nodes

The following sections describe additional routing features you might want to consider when planning
a PNNI network.

Preferred Routing

Preferred routes allow the switch administrator to define a specific route between the source and
destination nodes, and then specify this route as the preferred route when defining SPVCs. If the
connection is configured as a directed route, no other route is allowed, even if the route fails. If the
connection is not configured as a directed route, other routes are considered when the preferred route is
not available. When other routes are required, the switch can use the pre-calculated routing tables or
on-demand routing.
Preferred routing was introduced in Release 3.0.00 and is supported on the MGX 8830, MGX 8850
(PXM1E), MGX 8850 (PXM45), and MGX 8950 switches and the MGX 8880 Media Gateway. Release
3.0.20 and later support preferred routing on SES nodes.
Preferred routes created with Release 3 software cannot be gracefully upgraded to Release 4 or later
Note
preferred routes.
Part Number OL-3847-01 Rev. D0, April, 2004
AW maxCR
Required Required
Required Required
Required Required
Required Required
Required Required
AW—Selects the link with the least AW in the egress direction. This is the default.
AvCR—Selects the link with the largest AvCR in the egress direction.
maxCR—Selects the link with the largest maxCR in the egress direction.
loadbalance—Selects links randomly so that one link does not become overburdened while the
other is idle.
AvCR CTD CDV
Required Required Required
Required Required Required
Required Required —
Required — —
— — —
Cisco PNNI Network Planning Guide for MGX and SES Products, Release 5
Additional Routing Features in MGX and SES Nodes
1
CLR CLR
0
Required Required
Required Required
Required Required
— —
— —
2
0+1
4-7