[nm-wg] Re: [I2G2-Proto] NMWG schema comments (mainly about IPv6 and multicast)

[Dan Gunter]

Hi there,

I will add my two cents, with the caveats that I'm not very directly 
involved in this work any more and I'm only on my first cup of coffee.

>>
>> Endpoint =
>>        attribute value { xsd:string } &
>>        attribute type { "IPv4address" | "IPv6address" | 
>> "IPv4hostname" | "IPv6hostname } &
>>        attribute port { xsd:int }?
>
>
>>
>> Address =
>>        xsd:string &
>>        attribute type { "IPv4" | "IPv6" } 
>
>
I agree with both of you here, so why not make a specialized sub-schema 
for IP addresses? In a new namespace, perhaps 
"http://ns.ggf.org/nmwg/topo/ip/" or whatever the current incantation 
is. At the risk of being a strict constructionist, I suggest you could 
even have "../ip/4/" and "../ip/6/" sub-schemas to describe specifics of 
each protocol version. Either way, I think it's great if someone tries 
to sub-class all these things that are intended as general, as it is 
often the case that something too specific has crept in, like a thief in 
the night.

>>
>> COMMENT #3
>> ----------
>> Just a question. I don't understand InterfaceContent in nmwgtopo.rnc
>>
>> There is ipAddress and ifAddress. What is the difference? I guess 
>> ipAddress is the address used to reach the router while ifAddress is 
>> configured on the monitored interface? Maybe we should make that more 
>> explicit?
>>
>
> The ipAddress more or less the address of the chassis; it is an 
> administrative address that may be running some form of management 
> software.  The ifAddress is the particular address of an interface.  
> We have kept both as a courtesy to implementation designers; this may 
> prevent a forced lookup of an address saving valuable time and effort.
>
huh? if it's the "administrative" address, you should call it that. But 
I don't see this as generally applicable. Let caching be handled by the 
implementation.

I would think that what you need is the interface name/index and 
addresses. Given the note below, organized as a list of (address, 
interface name) pairs, where either or both can be repeated. Imitating 
the brilliant representation of traceroute :-)


-Dan

>>
>> COMMENT #4
>> ----------
>> Note an interface in IPv6 has by nature several IPv6 addresses. I 
>> mean unicast addresses here. There are link-local addresses (often 
>> only one derived from physical interface address) and one or more 
>> global unicast addresses.
>> It is I think necessary that ifAddress in InterfaceContent of 
>> nmwgtopo.rnc becomes a vector instead of just a single element? I 
>> guess we should display as well the link-local address... maybe 
>> having some type for it like "IPv6-LL")
>>
>
> We have only briefly dealt with ipv6 issues in the schemas, and we do 
> hope to encompass more features in the future.  It is possible to have 
> a 'list' element in a schema, although i am unsure of what 
> ramifications (if any) it would bring to the current design.  This is 
> something we should consider.

>