Cell Relay Archive

[Srikrishna <m_srikrishna@fujitsu-fnc.com>]

Here I go again with PNNI. Please bear with me while I am exposing my
total ignorance. It is not easy reading the PNNI spec. Hence the example
below.

I have a physical switch which is made up of two logical nodes. One of
them is the "lowest level node" and the other is the "Logical group
node". The functions of both these node are implemented in the same
physical switch.

Let us say,

The "lowest level node" part is identified as AESA address A.2.x.y where
A is 12 bytes, 2 takes up 1 byte, x is 6 bytes (ESI of the physical
switch which implements the lowest level node function)  and y = 0 is 1
byte (SEL) for a total of 20 bytes.

The "logical group node" part is identified as AESA address A.2.x.1
where A again is 12 bytes, 2 takes up 1 bytes, x is the same 6 bytes
(ESI of the physical switch whihc implements the LGN function) and y = 1
is 1 byte (SEL) for a total of 20 bytes.

Before I continue, Is the above theory correct or am I already screwed
up?

Anyway, assuming I am correct,

Peer group ID of the lowest level node = 104.A.2 where 104 is the level
of the peer group of which this "lowest level node" is a member of.

Node ID of the lowest level node part = 104.160.A.2.x.0 for a a total of
22 bytes

where 104 is the level of the "lowest level node's" containing peer
group which is 13 bytes (made up of A.2), 160 indicates that this is the
"lowest level node" and the remaining 20 bytes is the AESA address of
the "lowest level node" as indicated before.

Peer group ID of the LGN = 96.A where 96 is the level of the peer group
of which this LGN is a member of.

Node ID of the LGN = 96.104.A.2.x.0 for a total of 22 bytes

where 96 is the level of the LGN containing peer group which is 12 bytes
(made up of A), 104 indicates that it is a LGN of the peer group whose
level is 104 and the remaining 20 bytesis the AESA address of the
"lowest level node" as indicated before.

As one can see that the AESA addresss are different for both the "lowest
level node" and the LGN parts even though they are in the same physical
switch. This difference is in the SEL value (o for lowest level node and
1 for the LGN) as dictated in section 3.3.1 on page 19.

The LGN needs a AESA address obviously to setup an RCC SVC between which
may or may not be directly connected. Why does the "lowest level node"
need its own unique AESA address?. Is it because it may need to setup
SPVC/SPVP other than that I do not see the need from a signalling point
of view

Also the peer group ID's and the Node ID's are different as required. Am
I correct that when the AESA address and the level information are
configured into the switch, the peer group ID's and the node ID's are
automatically generated.

Can you confirm if I have derived these #' sabove correctly given the
initial AESA addresses.

How I am doing so far?. Now my main Q.

Even after talking out the above example out loud, I am not sure the
real need for a node ID.

Thanks for all the help in advance..

Srikrishna..

PS : The above represent my personal views NOT that of my employer.