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Task #2010

open

RIB cost guidelines

Added by Junxiao Shi over 9 years ago. Updated over 9 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
Docs
Target version:
-
Start date:
Due date:
% Done:

0%

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Description

Provide guidelines for how routing protocols should assign RIB cost.

Each routing protocol (including static) has its own way to assign costs.
Costs from different routing protocols are not necessarily comparable.

Forwarding does not interpret or use Cost assigned by routing protocol, but has access to an ordered list of nexthops in the FIB entry.
This order is determined by the Costs of Routes, even if they could come from different routing protocols.

This Task is to provide guidelines on how routing protocols should assign RIB cost, so that Costs from different routing protocols can be comparable.

Some routing protocols may use non-integer costs; the guidelines should recommend how to convert such costs into integers.


Related issues 1 (1 open0 closed)

Related to NLSR - Bug #5152: Problem of assigning link-cost to "zero" for neighbors in Hyperbolic Routing (HR) New03/22/2021

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Actions #1

Updated by Lan Wang over 9 years ago

Question is why different routing protocols' costs should be comparable. We won't have multiple intradomain routing protocols running at the same time on the same node. Interdomain and intradomain costs are not supposed to be comparable.

Actions #2

Updated by Junxiao Shi over 9 years ago

Routes can come from several sources:

  • static route (manually configured by nfdc register)
  • intra-domain routing protocol
  • inter-domain routing protocol
  • local application
  • remote prefix registration (laptop registers a prefix on the access router toward the laptop)

The costs from all those sources are not comparable, but forwarding is using an order derived from those costs.

Actions #3

Updated by Junxiao Shi over 9 years ago

At 20141031 conference call @Lan says:

@Beichuan suggests:

Define a range for local applications, and a range for external sources.
The range for local applications is smaller, so that they are preferred.

@Lan thinks this is similar to administrative distance. We are defining the preference of local applications statically.

@Lixia Zhang thinks the main question is to understand what Cost does other parties assign, as a reference of what Cost my application / routing protocol should assign.

Conclusion: we need to gain more experience in network operations before we can solve this problem.

Actions #4

Updated by Junxiao Shi almost 3 years ago

  • Related to Bug #5152: Problem of assigning link-cost to "zero" for neighbors in Hyperbolic Routing (HR) added
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