Enterasys Networks X-PeditionTM manual Adsl Limitations, Adsl Hardware, NIM Card

Features

Figure 13-4 IP over ATM Network Diagram

PC

PC

IP

802.3

PHY

IP

Frwd

Router / Modem

IP

1483

ATM

ADSL

ATM	ATM
DSL	SONET

DSLAM

Routed encapsulation - LLC/SNAP only

Access

Concentrator

Restrictions of this implementation are as follows:

•Maximum MTU of 1500 bytes

•NLPID-formatted routed IP version 4 PDUs over ATM PVCs are not supported

•LLC-encapsulated bridge PDUs are not supported. Any bridged PDUs received and PDUs received which specify a foreign MAC address (not the XSR’s) are silently discarded.

•Dynamic IP addresses acquired by DHCP are not supported

•ATM SVCs are not supported

ADSL Limitations

Consider the following caveats regarding ADSL operations on the XSR:

•The standard ADSL configuration reserves circuit 1/33 (VPI/VCI) as the Vendor Specific Channel) per ADSL Forum TR-008

•One Virtual Path only is supported

•The maximum overall MTU is 1500 bytes; default is 1492 bytes

•Bridging protocols and operations must be disabled on access concentrators

•ILMI protocols must be disabled on access concentrators

•One ADSL NIM card type is supported per XSR: Annex A or B.

•PPPoE connects to the first advertised service name only

ADSL Hardware

NIM Card

Two versions of the ADSL NIM are available for XSR Series 1800 and 3000 routers:

•Version 1 complies with ITU-T Recommendation G.992.1 Annex A - ADSL over POTS (Part #: NIM-ADSL-AC-01).

•Version 2 complies with ITU-T Recommendation G.992.1 Annex B - ADSL over ISDN (Part #: NIM-ADSL-B-01).

Caution: The XSR supports one installed ADSL NIM card type at a time (multiple installed cards must be of the same type).

XSR User’s Guide 13-5