[dhcwg] Review of draft-ietf-dhc-topo-conf-01

[Simon Perreault <[e-mail]>]

Here's my review...

Summary: Nicely written, very tutorial-like material. Nothing
controversial here. I like.

> 2. Terminology
> 
>    an IP address with a scope of use wider than the local link.

Is there something missing here? What is the term being defined?

> 5. Relay agent running on a host
> 
>    Relay agent is a DHCP software that may be run on any IP node.
>    Although it is typically run on a a router, it doesn't have to be
>    one.  Relay agent can be run on a host connected to two links.  That
>    case is presented in Figure 2.  There is router B that is connected
>    to links D and E. At the same time there is also a host that is
>    connected to the same links.  The relay agent software is running on
>    that host.  That is uncommon, but legal configuration.

Is there supposed to be a visual difference in figure 2 between relay E
and e.g. relay A? Is this text simply saying that router and relay are
two separate logical functions that are often, but not necessarily,
co-located? If so, maybe it would be useful to adjust figures 1 and 2
such that all relays that are also routers are identified as
"router+relay" or something like that.

>    However, all modern commercial DHCP servers handle name resolution by
>    querying the resolver each time a DHCP packet comes in.  This means
>    that if DHCP servers and DNS servers are managed by different
>    administrative entities, there is no need for the administrators of
>    the DHCP servers and DNS servers to communicate when changes are
>    made.  When changes are made to the DNS server, these changes are
>    immediately and automatically adopted by the DHCP server.  Similarly,
>    when DHCP server configurations change, DNS server administrators
>    need not be aware of this.

I would have liked further information on how DNS TTLs can/cannot be
reflected in DHCP. What are the impacts? Does reconfigure play a role?
Is the BCP to simply not care about TTL?

In addition, a comparison with geographic DNS would be very useful.

> 9. Relay Agent Configurations
> 
>    It's worth mentioning that although we talk about relay agents and
>    routers in this document mostly as if they are the same device, this
>    is by no means required by the DHCP protocol.  The relay agent is
>    simply a service that operates on a link, receiving link-local
>    multicasts or broadcasts and relaying them, using IP routing, to a
>    DHCP server.  As long as the relay has an IP address on the link, and
>    a default route or more specific route through which it can reach a
>    DHCP server, it need not be a router, or even have multiple
>    interfaces.

This section seems extremely redundant with section 5. Could they be
merged into one?

Simon
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