VSC7440 datasheet(158/444 Pages) MICROSEMI

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Functional Descriptions

VMDS-10492 VSC7440 Datasheet Revision 4.2

141

Frames with an illegal SIP can be redirected to the CPU using

CPU_RLEG_IP_HDR_FAIL_REDIR_ENA.

Use the ROUTING_CFG.IP6_DIP_ADDR_VIOLATION_REDIR_ENA parameters to configure each of

the following DIP address ranges to be considered illegal.

•

::/128 (unspecified address)

•

::1/128 (loopback address)

Frames with an illegal DIP can be redirected to the CPU using

CPU_RLEG_IP_HDR_FAIL_REDIR_ENA.

3.19.2.4 Unicast Routing

The IPv4/IPv6 unicast forwarding table in the Analyzer is configured with known routes. There are

typically two types of routes: Local IP and Remote IP.

•

Local IP networks directly accessible through the router. These entries return the DMAC address of

the destination host and correspond to an ARP lookup.

•

Remote IP networks accessible through a router. These entries return the DMAC address of the

next-hop router.

If frames are deemed suitable for IP unicast routing, a DIP lookup is performed in the Longest Prefix

Match (LPM) table. The lookup is a Classless Inter-Domain Routing (CIDR) lookup. That is, all network

sizes are supported.

For IP addresses in local IP networks without corresponding MAC addresses, LPM entry with a

corresponding ARP entry with a zero MAC address should be configured. This results in redirecting the

matching frames to the CPU and thus allows the CPU to exchange ARP/NDP messages with the stations

on the local IP networks to request their MAC address and afterwards use this information to update the

ARP table.

Packets with IVMID = EVMID (packets that are to be routed back to the router leg on which they were

received) can optionally be redirected to the CPU such that the CPU can generate an ICMP Redirect

message. This is configurable using VMID:RLEG_CTRL.RLEG_IP4_ICMP_REDIR_ENA and

VMID:RLEG_CTRL.RLEG_IP6_ICMP_REDIR_ENA.

If such packets are not redirected to the CPU, they are routed.

IVMID and EVMID are configured using VLAN:VMID_CFG.VMID and ARP:ARP_CFG_0.ARP_VMID.

The following illustration shows an IPv4 unicast routing example. IPv6 unicast routing works identically to

IPv4 unicast routing, with the exception that each of the IPv6 addresses occupies four times as much

space in VCAP LPM.

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