From: Amer Mdanat (amdanat) (amdanat@cisco.com)
Date: Thu Jul 31 2003 - 12:58:35 GMT-3
Guys here is a good explanation of the different fields of an ATM NSAP
[E.164] address:
1. Authority and format identifier (AFI) - identifies the type and the
format of the address [E.164, ICD or DCC this is a common field]
2. Data Country Code (DCC) - Identifies the country
3. High-Order Domain Specific Part (HO-DSP) - a combination of the
routing domain (RD) and the area identifier (AREA) of the NSAP address.
The ATM forum combined both together to support a flexible multilevel
addressing hierarchy for prefix based routing protocols (let me know if
you need information on this but I would not worry about it if I were
you).
4. End System Identifier (ESI) - specifies a 48-bit MAC address (note
that this does not have to be the MAC address [it defaults to it in most
vendor implementations] You can actually set any value if you want to
configure this manually but it is a very hectic job to do so and
extremely confusing!
5. Selector (SEL) - used by end stations (for local multiplexing) and
has no network significance (remember that this has nothing to do with
Cisco or non Cisco (should have nothing to do with the interface but I
think it is a good practice and if needed I can only see this important
for LANE implementations.
6. International code designator (ICD) - Identifies particular
international organisations.
7. E.164 - Indicates the BISDN E.164 address.
The order within the NSAP [E.164 format representation] address is as
follows:
________________________________________________________
| | | | |
|
| AFI | E.164 | HO-DSP | ESI | SEL
|
| | | | |
|
------------------------------------------------------------------------
--------------------------
| - - - - - - - - - - - - IDP - - - - - - - - - - >
| - - - - - IDI - - - - - - - - - - ->
Please note that other formats are possible but I did not include them.
Not all the fields explained are present in the NSAP (E.164) address
format. It is only the ones shown in the diagram. Other possible formats
are ICD (uses the ICD field instead of the E.164 and is much smaller)
and DCC format (naturally uses the DCC field instead of the E.164
format. Note that the HO-DSP, ESI and SEL are always present in all
formats!
P.S Those are ATM forum formats. The ITU-T standerised upon the use of
telephone-number like E.164 addresses only for PUBLIC (BISDN) networks.
Hope this explains it :-)
Amer
-----Original Message-----
From: phase90 [mailto:phase90@comcast.net]
Sent: 31 July 2003 04:35
To: Ian Stong; 'John Matijevic'; ccielab@groupstudy.com
Subject: Re: ATM selector byte???
Ian,
The LANE client for an elan can be put on any sub-interface
but the sub-interface running the server-bus must be on the
sub-interface matching the selector byte in the NSAP of the
server-atm-address found in the LANE database. A good reference is
Kennedy Clark's Lan Switching by CiscoPress. I have spent way too much
time on this technology. There are many other obscure facts about LANE
in this ook - it's ashame it's all obsolete now - for me anyway!
Jerry
----- Original Message -----
From: "Ian Stong" <istong@stong.org>
To: "'John Matijevic'" <matijevi@bellsouth.net>;
<ccielab@groupstudy.com>
Sent: Tuesday, July 29, 2003 10:18 PM
Subject: RE: ATM selector byte???
> Whenever I've configured it with subinterfaces, SVC's and an NSAP
> address I've had to set the 1 byte selector field to match the
> subinterface number. If you got it to work with it set to .00 with the
> same type scenario then perhaps I was doing something different from
> your scenario.
>
> Couple of Cisco references that may help as well:
>
> http://www.cisco.com/en/US/partner/products/hw/switches/ps1893/product
> s_
> command_reference_chapter09186a008007dec5.html
>
> "In the Cisco implementation of LANE, the prefix corresponds to the
> switch, the ESI corresponds to the ATM interface, and the Selector
> field corresponds to the specific subinterface of the interface."
>
>
> http://www.cisco.com/en/US/partner/products/sw/iosswrel/ps1831/product
> s_
> command_reference_chapter09186a0080080c8a.html
>
>
> Ian
> www.ccie4u.com
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of John Matijevic
> Sent: Tuesday, July 29, 2003 7:35 PM
> To: Ian Stong; 'Jonathan V Hays'; 'Tomasz Szymanski';
> ccielab@groupstudy.com
> Subject: Re: ATM selector byte???
>
> Hello,
> I kindly disagree with the last statement, I have implemented it with
> .00 always, and have used subinterfaces and it has worked for me. What
> happens
> if you subinterface is atm 0.234, then you cant set the selector bit
to
> .234. Just my .02 cents.
> Sincerely,
> Matijevic
> ----- Original Message -----
> From: "Ian Stong" <istong@stong.org>
> To: "'Jonathan V Hays'" <jhays@jtan.com>; "'Tomasz Szymanski'"
> <tomasz.szymanski@trecom.pl>; <ccielab@groupstudy.com>
> Sent: Tuesday, July 29, 2003 6:46 PM
> Subject: RE: ATM selector byte???
>
>
> > If you are using ATM subinterfaces with SVC's you will want to set
> > the selector byte to the subinterface number. For example if you
> > use
> ATM0.2
> > your NSAP address would need to end with .02
> >
> >
> > Ian
> > www.ccie4u.com
> > Rack Rentals and Lab Scenarios starting at $20
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Jonathan V Hays
> > Sent: Tuesday, July 29, 2003 4:40 PM
> > To: 'Tony Schaffran'; 'Tomasz Szymanski'; ccielab@groupstudy.com
> > Subject: RE: ATM selector byte???
> >
> > He is referring to the last byte (last 2 hex digits) of an NSAP
> address.
> > The more or less defunct LANE technology used the selector byte to
> > differentiate among multiple services on the same switch.
> >
> > Not sure what it is used for otherwise - most examples have it set
> > to 00.
> >
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Tony Schaffran
> > Sent: Tuesday, July 29, 2003 4:24 PM
> > To: 'Tomasz Szymanski'; ccielab@groupstudy.com
> > Subject: RE: ATM selector byte???
> >
> >
> > I am looking at the ATM cell structure. I do not see a selector
> > byte. Can you elaborate?
> >
> > Tony Schaffran
> > Network Analyst
> > CCIE #11071
> > CCNP, CCNA, CCDA
> > NNCDS, NNCSS, CNE, MCSE
> >
> > http://www.cconlinelabs.com/
> > Your #1 choice for online cisco rack rentals.
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of
> > Tomasz Szymanski
> > Sent: Tuesday, July 29, 2003 1:09 PM
> > To: ccielab@groupstudy.com
> > Subject: ATM selector byte???
> >
> > Hello,
> >
> >
> > Can someone tell me what is the purpose of the selector byte in ATM?
> >
> >
> > TS
> >
> >
> >
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