RAD Data comm 4-Wire Symmetrical VDSL Modem ASM-60 - Manual (Page 55)

Introduction C-1
Appendix C
IR-IP Interface Module
C.1 Introduction
Overview
IR-IP is a high-performance, miniature IP router based on RAD's unique IP router
chip, the ChipRouter.
IR-IP works by taking each Ethernet frame from the LAN and determining whether
the IP packet is destined for the IP net on the Ethernet LAN. If not, IR-IP forwards
the packet to the WAN (line) link. IP packets received from the WAN link are
automatically forwarded to the LAN if the IP net matches.
IR-IP includes hardware filters which handle all filtering operations at wire speed
from both LAN-to-WAN and WAN-to-LAN, without dropping a single packet.
Filtering and forwarding are performed at the maximum rate of 35,000 and
30,000 frames per second (wire speed), respectively. The buffer can hold
256 frames of maximum size of 1534 bytes and a throughput latency of one
frame.
IR-IP is available with 10BaseT (UTP) interface and is fully
IEEE 802.3/Ethernet v2 compliant. The IR-IP interface can also operate in full
duplex Ethernet applications.
ASM-60 equipped with IR-IP interface module can be used as a Frame Relay
Access Device (FRAD) with an integral IP router. RFC 1490 is supported for a
single DLCI on the WAN link. Detection of the DLCI and the maintenance
protocol is performed automatically. This allows the IR-IP to be used as the
termination unit of IP services over Frame Relay at the customer premises,
opposite a Frame Relay switch in the backbone.
Alternatively, Point-to-Point Protocol (PPP) can be run on the WAN link with
automatic negotiation on power-up, as well as support for PAP and CHAP
authentication. With this feature, IR-IP can operate opposite any PPP compliant
access server or backbone router.
IR-IP supports HDLC, which is especially important for broadcast and multicast
applications where bandwidth overhead is critical.
IR-IP supports IP multicast at wire speed, making it suitable for any multicast
environment including high speed downstream environments, such as satellite and
xDSL. Users on the LAN who register with IR-IP for an IP multicast group using the
IGMP protocol filter IP multicast packets at wire speed.
Management and advanced configuration are performed via Telnet.