[cisco-voip] CME ENUM Lookup Capability

[Andre Beck]

Hi Jason,

On Fri, Aug 08, 2008 at 03:48:05PM -0400, JASON BURWELL wrote:
> Does CME have the capability to do a DNS query to an ENUM server to
> route a SIP call to a destination IP address?

in theory, yes it has. Or rather the IOS voice gateway underlying
the CME has, it isn't CME specific. You have to configure an
enum-match-table and a SIP dialpeer with a session target pointing
to enum:<tablenum> and that should be it.

In practice, I've tested this years ago when ENUM was new and hot,
but IOS couldn't parse any NAPTR RR as found in the DNS. The format
had evolved, IOS used something that was no longer valid. It was
somewhat Ok then, as the change was just months before.

Just these days I tried it again using the shiny new and latest
12.4(20)T that apparently is shaping what 12.5 mainline is going to
be and found that NAPTR parsing is exactly as broken as it was in
the day:


sip-test#test enum 1 9008000101600
[...]
enum_resolve_domain: rule 6 result string 498000101600
generate_enum_search_string : search string 0.0.6.1.0.1.0.0.0.8.9.4.e164.org
enum_dns_query: name = 0.0.6.1.0.1.0.0.0.8.9.4.e164.org type = 35, ns_server = 0
order 200 pref 10 service E2U+SIP flag u
regexp !^\+49800(.*)$!sip:49800\1 at freecall.pbx-network.de! replacement 
num_elem = 1
NAPTR Record : order 200 pref 10 service E2U+SIP
               flags u regexp !^\+49800(.*)$!sip:49800\1 at freecall.pbx-network.de!
               replacement 
validate_service_field:  NAPTR Record format Error, non-supported "service protocol" field
find_enum_contact_list_i:  NAPTR Record format Error, invalid "service" field


It's sad. Given all the incomplete solutions abound, the success of
Skype is not really a mystery, even though we should all be using true
peer to peer ENUM+VoIP under purely our own control today, in the midst
of crumbling incumbent voice carrier's remains...

Andre.
-- 
   Real men don't make backups of their mail. They just send it out
    on the Internet and let the secret services do the hard work.

-> Andre Beck    +++ ABP-RIPE +++      IBH IT-Service GmbH, Dresden <-