Lucent Technologies CBX 3500 Configuration Manual page 413

Beta Draft Confidential
4. Select Ok when finished. The Add PVC dialog box will close.
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
Configuring ATM Over MPLS Gateway Solution on CBX 3500
Table 9-26. Add PVC: Pwe3 Tab Fields (Continued)
Field
Ctrl Word The control word (CW) is a four-octet header used in some
encapsulations to carry per packet information when the PSN
is MPLS. This field is optional for N:1 encapsulation. If one
end supports CW and the other end doesn't support CW, then
label mapping negotiation is performed and it is decided that
no CW is used in the forwarding dataplane.
This field is automatically populated based on what choice is
selected for the Pw Type:
•
•
Rmt Ctrl Word Populated automatically to match the Ctrl Word field.
Max Atm cells Specifies the maximum number of concatenated ATM cells
that can be processed as a single PDU by the egress PE. An
ingress PE transmitting concatenated cells on this PW can
concatenate a number of cells up to the value of this parameter,
but must not exceed it. This is applicable only to PW types 9,
0x0a, 0xc, and 0xd and is REQUIRED for these PW types. It
does not need to match in both directions of a specific PW.
This field is not user-configurable in this release. The default is
1.
TTL This field is populated automatically by the NMS. The default
is 2, as per the PWE3 standard.
Exp Bits Mode Indicates the way the PW shim label EXP bits are to be
determined. The value defaults to Outer Tunnel. Currently
there is no need to mark the PW label with the EXP bits since
the PW label is not visible to the intermediate nodes as it sits
under the PSN label, which is used by LSRs.
Exp Bits This field is not user-configurable in this release.
Configuring PWE3 Over MPLS Core Network
Description
If ATM N:1 (N=1) VCC cell Transport is the Pw Type, then
No Control Word populates this field and the control word
will not be sent with each packet by the local node.
If ATM 1:1 VCC cell Mode is the Pw Type, then With
Control Word populates this field and the control word is
sent by the local node with each packet.
1/19/059-67