Enterasys Networks X-PeditionTM manual Routed IP over ATM, PPPoE Network Diagram

Features

Figure 13-3 PPPoE Network Diagram

PC

PC

IP

802.3

PHY

IP	PPPoE
Frwd	Client

Router / Modem with

integrated PPPoE client

IP

PPP

802.3

1483

ATM

ADSL

DSLAM
ATM	ATM	Access
DSL	SONET	Concentrator

Bridge encapsulation

LLC/SNAP only

-no bridging PDUs

-no CRCs

-no ARP

-discard broadcast frames

-discard multi-cast frames

-discard PDUs without XSR’s MAC

The limitations of this configuration are as follows:

•Maximum MTU of 1492 bytes

•ARP is not supported

•Other received bridged PDU types are silently discarded (802.4, 802.5, 802.6, FDDI)

•Does not send (PID type 0x00-01) and ignores received (PID type 0x00-01) LAN FCSs

•Spanning tree protocols are not supported

•Any received PDU which does not specify the XSR’s MAC address are silently discarded

•The access concentrator must be configured with bridging and ATM ILMI disabled

•ATM SVCs are not supported

Routed IP over ATM

The XSR’s Routed IP over ATM (IPoA) method, as shown in Figure 13-4, supports the following subset of RFC-2684 as it relates to Routed IP PDUs:

•LLC encapsulated routed non-NLPID formatted IP version 4 PDUs over ATM PVCs

•Non-encapsulated routed IP v4 PDUs over ATM PVCs (virtual circuit multiplexing mode)

•Statically configured IP address

•IPoA is invoked by the encapsulation ipoa command.

Note: Your choosing the correct encapsulation method depends on the Customer Premises Equipment (CPE) support offered by your DSL provider.

13-4 Configuring ADSL