Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 738)

710 Multi-Service IronWare Routing Configuration Guide
53-1003033-02
IPv6 IS-IS single-topology mode
IPv6 IS-IS single-topology mode
IPv6 IS-IS supports single-topology mode, which means that you can run IPv6 IS-IS concurrently
with other network protocols such as IPv4 IS-IS throughout a topology. However, when
implementing a single topology, all routers in an area (Level 1 routing) or domain (Level 2 routing)
must be configured with the same set of network protocols on all its interfaces, even on loopback
interfaces. You can configure IPv4 IS-IS only, IPv6 IS-IS only, or both IPv4 IS-IS and IPv6 IS-IS
(
Figure 35 ). For example, to successfully implement both IPv4 and IPv6 IS-IS in an area, you must
configure both IPv4 and IPv6 IS-IS on all router interfaces in the area.
FIGURE 35 IPv6 IS-IS in single-topology mode
A single shortest path first (SPF) per level computes the IPv4 and IPv6 routes. The use of a single
SPF indicates that both IPv4 and IPv6 IS-IS routing protocols must share a common network
topology
The implementation of IPv4 IS-IS supports type, length, and value (TLV) parameters to advertise
reachability to IPv4 networks. The TLVs specify the types of data, the maximum length of the data,
and the valid values for the data. IPv6 IS-IS advertises its information using new TLV parameters.
The new TLV parameters for IPv6 support an extended default metric value.
In a single topology, if both IPv4 and IPv6 are configured on an interface, metric-style must be set
to wide in both address families. Narrow is the default for IPv4. Wide is the default for IPv6.
IS-IS CLI levels
The CLI includes various levels of commands for IS-IS. Figure 36 diagrams these levels that
includes the levels used for IPv6 IS-IS.