Resource sizing
Issue 3.4.1 June 2005
183
used) implies a total overhead of 11 bytes (88 bits) in this example. This implies the following
table of WAN bandwidths,
Table 39: IP WAN bandwidth requirements for media streams
, which
assumes the use of cRTP:
This table can be used in the WAN bandwidth calculation for the system in
Example 6: IP
bandwidth considerations
.
Example 8: WAN bandwidth
In
Example 6: IP bandwidth considerations
, the total IP WAN bandwidth usage between each
pair of sites was calculated, and expressed in Erlangs at the bottom of
Table 35: IP WAN
bandwidth usages (Erlangs) for Example 6: IP bandwidth considerations
on page 179.
Specifically, the total WAN bandwidth usage between Sites 1 and 2 is 24.0 Erlangs, between
Sites 1 and 3 is 10.0 Erlangs, and between Sites 2 and 3 is 4.0 Erlangs. This implies that the
average number of media streams simultaneously in use at any given time between Sites 1 and
2 is 24. Analogous statements can also be made regarding WAN traffic between each of the
other two pairs of sites.
Every media stream across the IP WAN, between any pair of sites, is assumed to use the
compressed G.729 codec, since bandwidth is relatively inexpensive within a private LAN, as
opposed to a public WAN. Assume, for the sake of this example, a standard IP packet size of 20
ms. For the G.729 codec,
Table 39: IP WAN bandwidth requirements for media streams
on
page 183 indicates that each (unidirectional) media stream consumes 12.4 kbps of IP WAN
bandwidth. Similar to the case in
Example 7: LAN bandwidth
, 24 is the average number of
simultaneous bidirectional media streams. As in
Example 7: LAN bandwidth
, the bandwidth is
sized to a “GOS” of P001 (“GOS” in this context is actually a pseudo-GOS; true GOS is
associated with a fixed number of channels, as is typical of circuit-switched systems). The
standard infinite-server queueing model implies that less than 0.1% of the time there is at least
40 simultaneous media streams between Sites 1 and 2. So, it is sufficient to engineer the WAN
bandwidth between those two sites to support 39 simultaneous media streams. Therefore, the
WAN between Sites 1 and 2 requires at least (39 simultaneous media streams) x (12.4 kbps per
media stream) = 484 kbps of bandwidth. This result, along with the analogous results for the
WAN traffic between the other two pairs of sites, are provided in
Table 40: IP WAN bandwidth
requirements in each direction, for Example 8: WAN bandwidth
on page 184.
Table 39: IP WAN bandwidth requirements for media streams
Packet “size”
(ms)
G.711 (kbps)
G.729 (kbps)
10
72.8
16.8
20
68.4
12.4
30
66.9
10.9
60
65.5
9.5
Содержание Application Solutions
Страница 1: ...Avaya Application Solutions IP Telephony Deployment Guide 555 245 600 Issue 3 4 1 June 2005 ...
Страница 20: ...About This Book 20 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 21: ...Issue 3 4 1 June 2005 21 Section 1 Avaya Application Solutions product guide ...
Страница 22: ...22 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 74: ...Avaya Application Solutions platforms 74 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 106: ...Call processing 106 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 124: ...Avaya LAN switching products 124 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 139: ...Issue 3 4 1 June 2005 139 Section 2 Deploying IP Telephony ...
Страница 140: ...140 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 186: ...Traffic engineering 186 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 204: ...Security 204 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 214: ...Voice quality network requirements 214 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 228: ...Avaya Integrated Management 228 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 239: ...Reliability Issue 3 4 1 June 2005 239 Figure 69 S8700 Media Server in a high reliability configuration ...
Страница 274: ...Reliability and Recovery 274 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 275: ...Issue 3 4 1 June 2005 275 Section 3 Getting the IP network ready for telephony ...
Страница 276: ...276 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 350: ...Implementing Communication Manager on a data network 350 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 356: ...Network recovery 356 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 366: ...Network assessment offer 366 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 367: ...Issue 3 4 1 June 2005 367 Appendixes ...
Страница 368: ...Appendixes 368 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 394: ...Access list 394 Avaya Application Solutions IP Telephony Deployment Guide ...
Страница 414: ...DHCP TFTP 414 Avaya Application Solutions IP Telephony Deployment Guide ...