DELL S6000-ON User Manual
IS area address, system ID, and N-selector. The last byte is the N-selector. All routers within an area have
the same area portion. Level 1 routers route based on the system address portion of the address, while
the Level 2 routers route based on the area address.
The NET length is variable, with a maximum of 20 bytes and a minimum of 8 bytes. It is composed of the
following:
the same area portion. Level 1 routers route based on the system address portion of the address, while
the Level 2 routers route based on the area address.
The NET length is variable, with a maximum of 20 bytes and a minimum of 8 bytes. It is composed of the
following:
• area address — within your routing domain or area, each area must have a unique area value. The first
byte is called the authority and format indicator (AFI).
• system address — the router’s MAC address.
• N-selector — this is always 0.
• N-selector — this is always 0.
The following illustration is an example of the ISO-style address to show the address format IS-IS uses. In
this example, the first five bytes (47.0005.0001) are the area address. The system portion is 000c.000a.
4321 and the last byte is always 0.
this example, the first five bytes (47.0005.0001) are the area address. The system portion is 000c.000a.
4321 and the last byte is always 0.
Figure 51. ISO Address Format
Multi-Topology IS-IS
Multi-topology IS-IS (MT IS-IS) allows you to create multiple IS-IS topologies on a single router with
separate databases. Use this feature to place a virtual physical topology into logical routing domains,
which can each support different routing and security policies.
separate databases. Use this feature to place a virtual physical topology into logical routing domains,
which can each support different routing and security policies.
All routers on a LAN or point-to-point must have at least one common supported topology when
operating in Multi-Topology IS-IS mode. If IPv4 is the common supported topology between those two
routers, adjacency can be formed. All topologies must share the same set of L1-L2 boundaries.
operating in Multi-Topology IS-IS mode. If IPv4 is the common supported topology between those two
routers, adjacency can be formed. All topologies must share the same set of L1-L2 boundaries.
You must implement a wide metric-style globally on the autonomous system (AS) to run multi-topology
IS-IS for IPv6 because the Type, Length, Value (TLVs) used to advertise IPv6 information in link-state
packets (LSPs) are defined to use only extended metrics.
IS-IS for IPv6 because the Type, Length, Value (TLVs) used to advertise IPv6 information in link-state
packets (LSPs) are defined to use only extended metrics.
The multi-topology ID is shown in the first octet of the IS-IS packet. Certain MT topologies are assigned
to serve predetermined purposes:
to serve predetermined purposes:
• MT ID #0: Equivalent to the “standard” topology.
• MT ID #1: Reserved for IPv4 in-band management purposes.
• MT ID #2: Reserved for IPv6 routing topology.
• MT ID #3: Reserved for IPv4 multicast routing topology.
• MT ID #4: Reserved for IPv6 multicast routing topology.
• MT ID #5: Reserved for IPv6 in-band management purposes.
• MT ID #1: Reserved for IPv4 in-band management purposes.
• MT ID #2: Reserved for IPv6 routing topology.
• MT ID #3: Reserved for IPv4 multicast routing topology.
• MT ID #4: Reserved for IPv6 multicast routing topology.
• MT ID #5: Reserved for IPv6 in-band management purposes.
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Intermediate System to Intermediate System