R3303-HP HSR6800 Routers Layer 3 - IP Routing Configuration Guide

352
different, routers supporting both IPv4 and IPv6 send IPv6 packets to routers that do not support IPv6,
and thus packet loss occurs.
To resolve this issue, configure IPv6 IS-IS Multi-Topology Routing (MTR) to perform route calculation
separately in IPv4 and IPv6 topologies.
Figure 103 Network diagram
In Figure 103, the numbers refer to the link costs. Router A, Router B, and Router D support both IPv4 and
IPv6. Router C supports only IPv4 and cannot forward IPv6 packets.
Enable IPv6 IS-IS MTR on Router A, Router B, Router C, and Router D to make them perform route
calculation separately in IPv4 and IPv6 topologies. With this configuration, Router A does not forward
IPv6 packets destined to Router D through Router B, avoiding packet loss.
For more information about MTR and IS-IS MTR, see "Configuring MTR" and "Configuring IS-IS."
Configuration prerequisites
Before you configure IPv6 IS-IS MTR, configure basic IS-IS functions, and establish IS-IS neighbors.
Configuration procedure
To configure IPv6 IS-IS MTR:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter IS-IS view.
isis [ process-id ] [ vpn-instance
vpn-instance-name ]
N/A
3. Specify the cost style for IS-IS.
cost-style { narrow | wide |
wide-compatible | { compatible |
narrow-compatible }
[ relax-spf-limit ] }
By default, narrow is adopted.
4. Enable IPv6 IS-IS MTR.
multiple-topology ipv6-unicast Disabled by default.
Displaying and maintaining IPv6 IS-IS
Router A Router B
Router D
Router C
IPv4
IPv4
36
5
4
3
IPv6
IPv6
IPv4
IPv4
IPv6IPv6