Reference Guide

Intermediate System to Intermediate System | 495
You can configure the system as a Level 1 router, a Level 2 router, or a Level 1-2 router. For IPv6, the IPv4
implementation has been expanded to include two new type, length, values (TLVs) in the PDU that carry
information required for IPv6 routing. These TLVs are IPv6 Reachability and IPv6 Interface Address.
Also, an IPv6 protocol identifier is included in the supported TLVs. The TLVs use the extended metrics
and up/down bit semantics.
Multi-Topology IS-IS adds TLVs:
•
MT TLV - contains one or more Multi-Topology IDs in which the router participates. This TLV is
included in IIH and the first fragment of an LSP.
•
MT Intermediate Systems TLV - appears for every topology a node supports. An MT ID is added to the
extended IS reachability TLV type 22.
•
Multi-Topology Reachable IPv4 Prefixes TLV - appears for each IPv4an IS announces for a given MT
ID. Its structure is aligned with the extended IS Reachability TLV Type 236 and it adds an MT ID.
•
Multi-Topology Reachable IPv6 Prefixes TLV - appears for each IPv6an IS announces for a given MT
ID. Its structure is aligned with the extended IS Reachability TLV Type 236 and adds an MT ID.
By default, FTOS supports dynamic host name exchange to assist with troubleshooting and configuration.
By assigning a name to an IS-IS NET address, you can easily track IS-IS information on that address.
FTOS does not support ISO CLNS routing; however, the ISO NET format is supported for addressing.
To support IPv6, the Dell Networking implementation of IS-IS performs the following tasks:
• Advertises IPv6 information in the PDUs.
• Processes IPv6 information received in the PDUs.
• Computes routes to IPv6 destinations.
• Downloads IPv6 routes to RTM for installing in the FIB.
• Accepts external IPv6 information and advertise this information in the PDUs.
The following table displays the default values for IS-IS.
Table 27-1. IS-IS Default Values
IS-IS Parameter Default Value
Complete Sequence Number PDU (CSNP) interval 10 seconds
IS-to-IS hello PDU interval 10 seconds
IS-IS interface metric 10
Metric style Narrow
Designated Router priority 64
Circuit Type Level 1 and Level 2
IS Type Level 1 and Level 2
Equal Cost Multi Paths 16