Subject: Re: [Bridge-mib] Question of link aggregation groups in Q-Bridge portList

From: Michael MacFaden <[email-masked]>
Date: Wed, 12 Dec 2001 11:11:59 -0800

On Wed, Dec 12, 2001 at 10:51:11AM -0800, chungwei wu wrote:
>Correct me if I am wrong - Back to the 30th bit set in portList example. The 
>manager will retrieve port ifIndex from the dot1BasePortTable by locating 
>the entry indexed by dot1BasePort with value of *30*. 

Incorrect.

A given bridge port is identified by dot1dBasePortNum. An EMS 
must start with dot1dBasePortTable to learn what "bridge ports" the 
transparent bridge has. 

A bridge port does not have to have an ifIndex and
the values do not have to be the same.

Please see http://www.nmops.org/download/understanding-snmp-counters.pdf 
page 48.

>Then it uses this ifIndex as a key to the ifTable to find more port related information such 
>as ifType. Since LAG is one of the ifType, the manager knows this port is a 
>logical LAG rather than a physical one.

Easier to use ifXTable ifConnectorPresent to determine if a port is
physical or logical (see page 46 of the above document).

I will answer your product specific questions separately.

Regards,
Mike MacFaden

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From: "chungwei wu" <[email-masked]>
Date: Wed, 12 Dec 2001 10:51:11 -0800

Correct me if I am wrong - Back to the 30th bit set in portList example. The 
manager will retrieve port ifIndex from the dot1BasePortTable by locating 
the entry indexed by dot1BasePort with value of *30*. Then it uses this 
ifIndex as a key to the ifTable to find more port related information such 
as ifType. Since LAG is one of the ifType, the manager knows this port is a 
logical LAG rather than a physical one.

One more question about RS platform SNMP Management:

Page 63 in Appendix D: ...The dot1dBasePort index assigned to the smart 
trunk will start with the value in the 513. These values are arbitrary and 
device specific.

So RS reserves a port number segment for the smart trunks starting from 513. 
If there is a smart trunk provisioned and is selected, the length of 
portList will be at least 513.

However, RFC2674 page 15: Port numbers are in the range   
(1..dot1dBaseNumPorts). Then the RS smart trunk port number may not in this 
range if the number of port capable of bridging is less than 513. I may 
misunderstand something here.

Regards,
Chungwei

>From: Michael MacFaden <[email-masked]>
>To: chungwei wu <[email-masked]>
>CC: [email-masked]
>Subject: Re: [Bridge-mib] Question of link aggregation groups in Q-Bridge 
>portList
>Date: Tue, 11 Dec 2001 15:24:52 -0800
>
>On Tue, Dec 11, 2001 at 10:44:42AM -0800, chungwei wu wrote:
> >Should the port number in portList be equal to the dot1dBasePort?
>
>By definition.
>
>RFC 2674, section 3.4.2, page 15:
>    Each port is uniquely identified by a port number.  A port number has
>    no mandatory relationship to an interface number, but in the simple
>    case a port number will have the same value as the corresponding
>    interface's interface number.  Port numbers are in the range
>    (1..dot1dBaseNumPorts).
>
> >For example, if the 30th bit is set, how does EMS know which port is set?
> >Look like they need to be the same, otherwise, another mapping is 
>required.
>
>Precisely.  EMS will typically read dot1dBasePortTable to track
>the set of "ports" that make up the 802 transparent bridge.
>
>dot1qVlanCurrentTable then maps dot1dBasePortNums to FDB which
>then is mapped to VID.
>
>Next, zero or more instances of Spanning Tree Protocol may be employed.
>In such cases, the BRIDGE-MIB contains the first instance, and
>the Entity MIB may be used to track subsequent instances of STP.
>
>BTW, same goes for OSPF MIB module. ISIS MIB module however chose to fix 
>their
>table indexing to natively support multiple instances.
>
>The SNMPCONF working group draft:
>http://www.ietf.org/internet-drafts/draft-ietf-snmpconf-bcp-07.txt
>has some commentary/examples on the above...
>
>Regards,
>Mike MacFaden

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