User Manual
Product information and planning
9500 MPR Rel. 3.1
3DB18809AAAA Issue 1188/980
2.8.17.3.2 Protocol Stack Termination
In this release the ATMoMPLS protocol stack is terminated directly by the MPR NE where native ATM
interface is present (i.e. MPLS Tunnel Label, if present, is added by ASAP Card).
That implies all MPR NEs must be aware of MPLS Tunnel Label presence, i.e. to apply ATM PW Header
Compression.
2.8.17.3.3 802.1q VLAN Tag
ATMoMPLS protocol stack used by MPR foresees to have the 802.1q VLAN Tag.
VLAN is used, within MPR network, to define for ATM PW frames:
– forwarding plane
– colour marking consequent to profiled scheduling
– specific processing (ATM PW Header Compression) and QoS (queue assignment and colour-based
policing) on radio interfaces
The same VLAN ID can be used by several ATM PW flows only if they share the same CoS and forwarding
plane. Thinking to future releases, to use the same VLAN ID, the ATM PW flows must also share the same
encapsulation format (i.e. N-1 cell mode with or without Control Word, AAL5 SDU or PDU modes)
A VLAN ID that is used by ATM PW flow(s) can never be used for TDM flows.
The fields of the 802.1Q VLAN Tag to be inserted into ATM PW flow frames are assigned in the following
manner:
– 12-bit VLAN ID will be provisioned by ECT/NMS
– 3-bit PCP field is assigned according to the ATM PW flow COS and packet profiled scheduling
– 1-bit CFI field is set to 0
2.8.17.3.4 VLAN Swap
VLAN Swap feature is foreseen on "hand-off" MPR NE, i.e. the NE connected to IP/MPLS network.
VLAN Swap means that ATM PW flows ingressing/egressing the "hand-off" MPR will have the same com-
mon "external" VLAN ID, while within MPR network each ATM PW flow will use its own "internal" VLAN
ID (may be shared among several ATM PW flows with same path and CoS).
To avoid possible configuration clashing, the above "external" VLAN ID should belong to the allowed
range. Moreover, the "external" VLAN ID should be different from each "internal" VLAN ID.
VLAN Swap performed by the "hand-off" MPR NE is based on:
– for ingress, IP/MPLS network -> MPR network direction: the Inbound PW Label value
– for egress, MPR network -> IP/MPLS network direction: ATM PW CoS (to reduce numbers of "rules"
used for such mapping).
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