16 травня 2008 р. 23:37 Artem Naluzhnyy <
tut@nhamon.com.ua> написав:
> Ще таке питання: а щось (переваги) кардинально поміняється з SIP-адресацією
> та/або резольвінгом, якщо замість виключно VoIP-викликів передбачатимуться і
> аудіовідео-виклики? Типу, відеотелефонія та відеоконференцзв"язок (як
> "точка-точка", так і "многоточка").
Ні. Адресація абонентів характерна для сигналізації, якій байдуже
кількість та характеристики медіа-потоків.
Ага... ну ясно, дякую.
> Ну і може хто знає - як там зараз справи з реалізацією протоколу
> H.460.18/.19 (це якраз для забезпечення firewall/NAT traversal)?
> Реально його вендори (Tandberg, Polycom, Huawei etc) підтримують? Бо
> заявляють, що ага. Але як воно насправді?
Хіба H.460.17-.19 не для стеку H.323? В мережі будуть співіснувати SIP та H.323?
Для стеку. Принаймі ось чувак один каже
"The ITU (International Telecommunications Union – a
United Nations Agency) has ratified a new set of recommendations
(standards to most people) that promises to make NAT-firewall traversal
between vendors' videoconferencing equipment and different end user
organizations much easier in the future. The new recommendations are
H.460.18 (edited by TANDBERG) that enables H.323 video endpoints to
exchange signaling information, and H.460.19 (edited by RADVISION) that
defines the NAT-firewall mechanism for media. The two standards
obviously work together closely, but by keeping them separate, the
architecture will enable cleaner upgrades and enhancements in the
future, perhaps similar to the ISO 7-layer stack model for network
protocols. (Don't ask us whatever happened to H.460.1 through H.460.17,
which like MPEG 3, 5, and 6 shall forever remain a mystery.)
H.460 takes NAT-firewall traversal into the area of the service
provider or network cloud as well as the enterprise. Until now, any
organization could implement its own method or solution for
NAT-firewall traversal, but when it came time for inter-enterprise
H.323-based voice/video communications, there was no standard to handle
the situation. Now, this barrier disappears, providing a MAJOR
capability for IP communications between organizations. Yes, things are
getting better. Easier that is, when people understand how to register
to session border controllers, and when session border controllers know
how to neighbor.
Where the rubber meets the road, in terms of actual deployment, H.460
will require two things. The first is client software running behind
the firewall - typically inside the videoconferencing endpoints
themselves, or a gatekeeper substitute for non-compliant endpoints (see
below). The second implementation element is a device (session border
controller) in the network cloud, typically provided by the network
service provider.
If this sounds familiar to you, it may be because you remember
TANDBERG's announcement of its Expressway product line (WRB Vol 6 #05,
Feb 7), a product based on technology the company acquired with its
Ridgeway acquisition. In fact, H.460 is based on Expressway, but has
some minor modifications in the registration packet handling protocol
(not minor if you are a registration packet protocol software engineer
perhaps)."
Поки-що не знаю чи буде разом з SIP співіснувати і Н.323.
А SIP-based інфраструктура як вирішує питання з Firewall Traversal? Через proxy, чи якось іншим чином?