Technical data

Architecture and System Requirements

EN4442EN00EN_0002

Siemens

2 Architecture and System Requirements

2.1 Prerequisites

Prior to installing IP line gateways at a customer site a network assessment is required that will

determine whether the customer’s IP network is capable of supporting IP phones. This network

assessment will analyze the IP network and determine parameters like jitter, packet loss,

available bandwidth, supported QOS mechanisms and assess overall VoIP readiness.

2.2 Power Requirements

The HG 3500 line gateway is a standard HiPath 4000 card that plugs into standard HiPath 4000

enclosures (AP 3300 and AP 3700 Access Points). However, HG 3500 cards require more than

average power due to components with high power demands (DSPs). This limits the total

number of HG 3500 cards to a maximum of 6 cards per AP 3700 IP (9 slot), 10 cards per AP

3700 (13 slot) and 5 cards per AP 3300.

2.3 Network Requirements

The HG 3500 place high demands on the network via which it is coupled to its IP endpoints.

Just like Voice-over-IP data streams are sensitive to packet runtime, runtime variance (jitter)

and packet loss.

The availability and reliability of a HG 3500 system depends heavily on the quality of the IP

network used.

Therefore, the network must be examined prior to installation with regard to its suitability for

VoIP for the use of HiPath 4000 HG 3500. More details can be found in the HiPath Network

Analysis Guide.

All HiPath 4000 components must be connected to their own ports on Layer 2 switches.

Using hubs together with HiPath 4000 can cause problems. For this reason, they are not

permitted for use in corresponding VoIP scenarios. If hubs are available, they should be

replaced with a switch.

In order to achieve a high Quality of Service (voice quality/real time behavior of signaling), the

support of IEEE 802.1 p/q VLAN Tagging and IETF RFC 2474 DiffServ is recommended.

Note

If an access point is connected over Wide Area Networks in which the available

bandwidth is extremely restricted, the control information (signaling) and voice

data (payload) for access points must be given priority over other services.