Local Atm Passthrough; Vcc Cell Relay Encapsulation - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - LINK LAYER CONFIGURATION GUIDE 2010-10-13 Configuration Manual

JunosE 11.3.x Link Layer Configuration Guide

Local ATM Passthrough

VCC Cell Relay Encapsulation

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aal5snap—LLC/SNAP
aal5mux ip—VC-based multiplexing
aal5autoconfig—LLC/SNAP or VC-based multiplexing. (See "Configuring Dynamic
Interfaces" on page 511.)
aal5all—Martini encapsulation
NOTE: The Juniper Networks E120 and E320 Broadband Services Routers
do not support Martini encapsulation (aal5all) in the current release.
E Series routers support local ATM passthrough for ATM layer 2 services over Multiprotocol
Label Switching (MPLS). Local ATM passthrough enables the router to emulate
packet-based ATM switching. The ATM passthrough feature is useful for customers who
run IP in most of their network but still have to carry a small amount of native ATM traffic.
Local ATM passthrough uses ATM Martini encapsulation to emulate ATM switch behavior.
You can create pairs of cross-connected ATM VCs within the router. The router then
passes AAL5 traffic between two VCs, regardless of the contents of the packets.
You can also use AAL0 encapsulation when you configure a local ATM passthrough
connection. AAL0 encapsulation causes the router to receive raw ATM cells on this circuit
and to forward the cells without performing AAL5 packet reassembly.
For more information, see chapter Configuring Layer 2 Services over MPLS in JunosE BGP
and MPLS Configuration Guide.
E Series routers support virtual channel connection (VCC) cell relay encapsulation for
ATM layer 2 services over MPLS. VCC cell relay encapsulation is useful for voice-over-ATM
applications that use AAL2-encapsulated voice transmission.
VCC cell relay encapsulation enables the router to emulate ATM switch behavior by
forwarding individual ATM cells over an MPLS pseudowire (also referred to as an MPLS
tunnel) created between two ATM VCCs, or as part of a local ATM passthrough connection
between two ATM 1483 subinterfaces on the same router. The E Series implementation
conforms to the required N-to-1 cell mode encapsulation method described in the Martini
draft, Encapsulation Methods for Transport of ATM Over MPLS
Networks—draft-ietf-pwe3-atm-encap-07.txt (April 2005 expiration), with the provision
that only a single ATM virtual circuit (VC) can be mapped to an MPLS tunnel.
For more information, see chapter Configuring Layer 2 Services over MPLS in JunosE BGP
and MPLS Configuration Guide.
NOTE: The E120 and E320 routers do not support ATM over MPLS with VCC
cell relay encapsulation in the current release.
Copyright © 2010, Juniper Networks, Inc.