Cisco BPX 8600 Series, Руководство по установке и настройке

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Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 25 Configuring BXM Virtual Trunks
General Procedure to Set Up a Trunk
•
Vtrk is the virtual trunk number, which (for BNIs) can be 1–32 for T3/E3 or 1–11 for OC-3/STM1.
Note that the two ends of a virtual trunk can have different port interfaces. For example, a virtual
trunk supported by a UXM-OC-3 on one end can be supported by a BXM-T3 at the other end.
However, both ends of the trunk must have the same trunk bandwidth, connection channels, cell
format, and traffic classes. The
addtrk
command verifies this when you add the trunk.
Setting up a BXM or UXM Virtual Trunk through an ATM Cloud
This example is a general explanation of how to set up a virtual trunk through a BPX or IGX cloud:
Step 1 Obtain a VPC from the ATM cloud provider.
Step 2 Set up cables by doing the following: in the cloud network, physically connect a BXM port to each
BXM port that is likely to carry virtual trunks.
Step 3
For each port connected to a BXM virtual trunk port, use the following configuration sequence:
upln slot.port
upport slot.port
cnfport slot.port, and set the Shift parameter to “H" for shift.
The Shift/No shift parameter specifies whether or not the VCI bits in the cell header should be shifted
based on the HCF field of the cell header on cells arriving from the backplane. It is how Cisco networks
convert STI cells to standards based cell formats and similarly how standards-based cell formats are
converted back to STI cells. See Table 25-6 for some general guidelines on how to set the Shift
parameter when using virtual trunking through a cloud of non-Cisco equipment versus Cisco equipment
using BXMs.
If the network has BNI cards, or if the VPC can route over BNIs, set the
cnfport
Shift parameter to "H".
This causes the cell, when transported over a public network, to shift these bit spaces to restore them to
their normal location that they can be used across a network expecting a standard ATM cell header. If,
however, the route through the cloud traverses all BXMs, for example, then configure the
cnfport
command to No shift (on the port’s entry point into the cloud).
For UXM cards, you cannot configure the
Shift
parameter—the Shift setting is always
N
, or
Shift off
.
Step 4 Execute addcon. In the cloud network, add a virtual path connection for each end of the virtual trunk
that is to be routed through the cloud. An example of the syntax for this is:
addcon joker 5.1.1.* swstorm 6.2.10.*
where 5.1 and 6.2 are ports that are hooked up and configured for virtual trunking. DACS connections
are acceptable.
Note that the third number is the VPI, which must correspond to the virtual trunk VPI configured with
cnftrk in step 4. For UXM/BXM UNI virtual trunks, the useable range of VPIs is 1 to 255. For
UXM/BXM NNI virtual trunks, the useable range of VPIs is 1–4095.
Table 25-6 General Guidelines on setting cnfport Shift on/Shift off Parameter for Virtual Trunking
Non-Cisco Cloud Cisco BXM Cloud
BNI Virtual Trunks Shift off Shift off
BXM/UXM Virtual Trunks Shift off Shift on