Subject: FIB Terminology document: comments from Jerry Perser

From: [email-masked]
Date: Tue, 12 Dec 2000 16:18:33 -0700

Hi all,

At the bmwg meeting on Monday, Jerry gave me a marked up copy of my FIB
terminology draft with his comments.  For the benefit of the working group,
I'll list out his comments.  I hope I capture them all correctly!

Here they are ...

- 5.2 Network Prefix Length
	- Rephrase "refers to the length in bits of a network prefix" 
     	  to "Number of bits used to define the network prefix"
	- measurement units should just be "bits"

- 5.3 Forwarding Information Base (FIB)
	- indicate that the FIB is separate from the "routing table"
	  (i.e. the RIB).  Indicate that there are no secondary paths	
	  in the FIB
	- remove text describing the longest length prefix match
	  algorithm (out of place)

- 5.5 Forwarding Information Base Size
	- add text to indicate that the size refers to the total number
	  of active routes within the FIB.  That is, the FIB could 
	  potentially hold routes that a router might not be able to use
	  to forward packets - this definition indicates the total number
	  of routes inside the FIB that can and are used to forward 
	  packets
	- measurement units, instead of being "positive integer" should
	  be "number of routes"

- 5.6 Forwarding Information Base Prefix Distribution
	- in the 3d paragraph in the discussion, change "will have an 
  	  impact" to "may have an impact"
	- for measurement units, suggestion is to stay away from 
	  percentages of network prefixes to indicate the distribution.
	  Instead, use absolute number of routes to eliminate any 
	  uncertainty as to the number of routes advertised into the
	  router.  I.e. instead of a list like:
		{[/16, 10%], [/20, 36%], [/24, 54%]}
	  use (in the case that we're advertising 1000 routes):
		{[/16, 100], [/20, 360], [/24, 540]}

- 5.7 Maximum Forwaring Information Base Size
	- measurement units should be "number of routes"

- 5.8 Forwarding Information Base Learning Time
	- change the definition in the first paragraph from "The
	  forwarding information base learning ime is the time taken
	  for a router to receive and ..." to "The time a router
	  takes to process ..."
	- add measurement units "prefixes per second"

- 5.9 Per-Interface Forwarding Information Base
	- comment as to whether this was per-interface or per-card
	- what is the effect?

- 5.14 Route Aggregation
	- in the discussion section, suggested that route aggregation
	  within the router could be turned on or off, but that the
	  routes advertised into the router must be controlled and
	  monitored in order to avoid aggregation

- 5.15 Fully Meshed Traffic Flows
	- this definition is a repetition of "fully meshed traffic", 
	  indicated in RFC 2285.  
	- although the intention with this definition is to indicate
	  that packets from every port should be sent to every 
	  network prefix advertised on every other port, this is more
	  of an application, rather than a definition.  I.e. this 
	  should be covered in the methodology, rather than in the
	  terminology.

- other suggestions
	- add a definition for "longest length prefix match"
	- perhaps copy a little more text from RFC 2544/1242 rather 
	  than just referring to it continuously

I'll send out another email capturing the comments from the meeting on
monday.

See ya,

Guy

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Guy Trotter
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