[Isis-wg] an ISIS MIB question

[Jeff Parker]

> I have the following MIB questions:
> 
>   In isisISAdjTable, isisISAdjNeighborSysType
> can have the values: 3(intermediate system), 4(L1 system), 
> 5(L2 system). Why do you need the value of 3 when there 
> are already enumerations used for L1 and L2 systems?

Good question. I'll look at that for the next draft.  

>   Also, isisISAdjNeighSysID has a length of 12 octets.
> a SystemID has up to 8 octets. Why does this ID
> need some extra octets?

The extra octets are to store the extended circuitId
as described in DKatz's 3-way handshake draft (see below).  
While that is still just a draft, I cannot cite it directly.

I have placed the systemId first, as that makes more
sense for someone walking the table.   

isisISAdjNeighSysID OBJECT-TYPE
    SYNTAX OCTET STRING (SIZE(0..12))
    MAX-ACCESS read-only
    STATUS current
    DESCRIPTION
        "The system ID and circuit ID of the neighboring
        Intermediate System set from the source ID field
        of the neighbor's IIH PDUs."
    REFERENCE "{ISIS.aoi neighbourSystemIds (83)}"
::= { isisISAdjEntry 7 }

Compare to 

3.1  Syntax

   A new IS-IS Option type, "Point-to-Point Adjacency State", is
   defined:

          Type = 0xF0 (decimal 240)
          Length = 5 to 17 octets
          Value:
            Adjacency State (one octet):
              0 = Up
              1 = Initializing
              2 = Down
            Extended Local Circuit ID (four octets)
            Neighbor System ID if known (zero to eight octets)
            Neighbor Extended Local Circuit ID (four octets, if Neighbor
              System ID is present)

>   I noticed that isisISAdjIPAddrTable does not have
> as much information as isisISAdjTable. Information
> such as the type of neighboring systems and 
> the type of the adjacencies are not in the IP table.
> Is there any way to bridge these two tables?

I've tried to keep them distinct: there may be systems
that run ISIS that do not route IP traffic.  

> I am wondering if there is an efficient way of obtaining
> all neighbor system information given an IP of the
> local system. 
> 
>   Which table contains the area address(es) of the local
> system, isisISAdjAreaAddrTable 

Do you have suggestions for any edits that would make it clearer?

"This table contains the set of Area Addresses of
neighboring Intermediate Systems as reported in received IIH PDUs."

> isisManAreaAddrTable?

"The set of manual area addresses configured on this
Intermediate System."

> The isisISAdjAreaAddrTable is indexed on 
> isisISAdjAreaAddrSysInstance, isisISAdjAreaAddrCircIndex,
> and isisISAdjAreaAddrAdjIndex. What if there are more
> than one area addresses for a neighbor? These indices
> cannot differentiate multiple addresses from the same
> neighbor sent on the same circuit.
>  
> Thanks.
> 
> James

Good point.  Let me mull that over.  

- jdp