Subject: [forces] comments #12

From: Jamal Hadi Salim <[email-masked]>
Date: Tue, 16 Aug 2011 06:52:01 -0400

Ok, more comments:

------
30) 5.3.2.2
instead of "neighboring LFB" could you use the term
"downstream LFB" - this applies all over the rest of the document.

31)
"MediaEncapInfoIndex, the index we pass onto the neighboring LFB
instance. This index is used to lookup a table (typically media
encapsulatation related) further downstream. The CE sets it to a
value that is not allocated in downstream LFB tables. (If a
downstream LFB lookup fails to find it, it indicates some other
way to resolve it may be needed.)"
to:
"MediaEncapInfoIndex, the index we pass onto the downstream LFB
instance. This index is used to lookup a table (typically media
encapsulatation related) further downstream.
In some cases, depending on implementation, the CE may set the
MediaEncapInfoIndex passed downstream to a value that will fail
lookup when it gets to to a target LFB; such a lookup failure is
an indication that further resolution is needed. For an example of
this approach refer to section XXX which talks about ARP .."
32) 5.3.3.1
"This LFB performs the IPv6 unicast LPM table looking up. It always
expects as input IPv6 unicast packets from one singleton input known
as "PktsIn". Then the LFB uses the destination IPv6 address of every
packet as index to look up the IPv6 prefix table and generate a hop
selector as the matching result. This result will associate to the
packet as a metadatum to output to downstream LFBs, and will usually
be used there as an index to find more next hop information."
to:
"This LFB performs the IPv6 unicast LPM table look up. It always
expects as input IPv6 unicast packets from one singleton input known
as "PktsIn". The destination IPv6 address of an incoming packet
is used as content key to look up the IPv6 prefix table and generate a hop
selector. This generated result is associated to the
packet as a metadatum sent to downstream LFBs, and will usually
be used in those LFBs as an index to find more next hop information."

XXX: What happens on failure of lookup?
33)
"Three singleton output ports are defined to output LPM results.  "
to:
"Three singleton output ports are defined.  "

34)
"The first singleton output known as "NormalOut", which will output
IPv6 unicast packets that has passed the LPM lookup and got a hop
selector as the lookup result. The hop selector is associated with
the packet as a metadatum. Followed the normal output of the LPM LFB
is usually a next hop application LFB, like an IPv6NextHop LFB."
to:
"The first singleton output known as "NormalOut" outputs
IPv6 unicast packets that succeed the LPM lookup (and got a hop
selector). The hop selector is associated with
the packet as a metadatum. Downstream from the LPM LFB
is usually a next hop application LFB, like an IPv6NextHop LFB."

35)
"A default route flag is defined in the LPM table to enable the LFB to
support a default route, and loose RPF also. When set true, the
table entry is identified a default route and as a forbidden route
for RPF also. "
to:
"A default route flag is defined in the LPM table to enable the LFB to
support a default routeas well as loose RPF. When this falg is set true,
the table entry is identified a default route which also implies
that the route is forbidden for RPF. "
36)
"The IPv6PrefixTable component is defined as an array component of the
LFB. Each row of the array contains an IPv6 adrress, a Prefix
length, a Hop Selector, an ECMP flag and a Default Route flag. The
LFB uses the destination IPv6 address of every input packet as index
to look up this table to get a hop selector as the result. The ECMP
flag is for the LFB to support ECMP. The default route flag is for
the LFB to support a default route and for loose RPF."
to:
"The IPv6PrefixTable component is defined as an array component of the
LFB. Each row of the array contains an IPv6 address, a Prefix
length, a Hop Selector, an ECMP flag and a Default Route flag.
The ECMP flag is so the LFB can support ECMP. The default route flag is for
the LFB to support a default route and for loose RPF as described earlier."

Note: there was a typo in the original text "adrress"

Note:
This LFB serves again as a good example of what i was concerned about
earlier.  You should describe operations in the data handling section.
The components section should only talk about components details.
----

cheers,
jamal

---

From: "Wang,Weiming" <[email-masked]>
Date: Mon, 29 Aug 2011 22:06:12 +0800

Pls see inline for the response. 

Chuanhuang, pls take care of the message inside.

thanks,
Weiming

----- Original Message ----- 
From: "Jamal Hadi Salim" <[email-masked]>

> Ok, more comments:
Fixed all the document except xml file. Chuanhuang may help to check it in the xml. 

> this approach refer to section XXX which talks about ARP .."
Fixed. And also fixed the identical text in 5.3.4.2  for IPv6NextHop. 

Fixed.  

> XXX: What happens on failure of lookup?
Chuanhuang, pls reply this question. I also found theres no definition on this. We only have outputs for NormalOut, ECMPout, and ExceptionOut. 
The same is also for the IPv4UcastLPM LFB definition. 

> "Three singleton output ports are defined.  "
done.

> is usually a next hop application LFB, like an IPv6NextHop LFB."
done. also fixed identical text in 5.3.1.1 for IPv4UcastLPM.

> that the route is forbidden for RPF. "
Fixed.

> the LFB to support a default route and for loose RPF as described earlier."
Fixed.

---

From: "Chuanhuang Li" <[email-masked]>
Date: Tue, 30 Aug 2011 22:15:20 +0800

>The same is also for the IPv4UcastLPM LFB definition. 

We have defined an execption: "Packets can not find any routes in the prefix table."  These 
packets will go out from "ExceptionOut" LFB port. The same as IPv4UcastLPM LFB. Please see
Data Handling section. 

Yours,
Chuanhuang

---

From: "Wang,Weiming" <[email-masked]>
Date: Wed, 31 Aug 2011 20:21:43 +0800

----- Original Message ----- 
From: "Chuanhuang Li" <[email-masked]>
> packets will go out from "ExceptionOut" LFB port. The same as IPv4UcastLPM LFB. Please see
Ok, I'l add some text to describe it. 

thks,
Weiming

---

From: "Wang,Weiming" <[email-masked]>
Date: Thu, 1 Sep 2011 10:12:21 +0800

Chuanhuang, 

> packets will go out from "ExceptionOut" LFB port. The same as IPv4UcastLPM LFB. Please see

Changed the exception name to: 
. The packet failed the LPM lookup of the prefix table. 

The same change aslo applied to IPv6UcastLPM LFB. 
pls change the XML file also.

Weiming