3Com's RFI Focuses On Stackable Switches: Page 3 of 3

POWER AND VOICE
TacDoh is moving to a voice-over-IP system, and to keep costs down the company plans on using existing physical network jacks rather than running new cable for VoIP phones. The 3Com access switches will need to supply reliable Power over Ethernet to our VoIP phones. 3Com recommends we deploy its Remote Power System external AC or DC power supply to provide redundant power for the switch, as well as powering the PoE ports at 15.4 watts each. The RPS is provided by Eaton Powerware.

Like other switches supporting PoE, the 5500 and 4200 devices can supply power based on the discovery of the type of phone attached to the port. The switches ship with profiles for many 3Com and non-3Com phones and devices.

TacDoh also can prioritize so that mission-critical devices will get power before lower-priority gear. For example, the 5500 has 300 watts and can power 19 devices at 15.4 watts, well short of the 24- or 48-port models. If the RPS fails, the draw might exceed the available power. Prioritization allows the switch to disable power to low-priority gear first.

Voice devices, once detected, can be placed in a voice virtual LAN reserved exclusively for VoIP traffic. When a PC is connected to a phone--a common configuration--the switch will place the VoIP traffic into the voice virtual LAN and the data traffic into the appropriate data virtual LAN.

KEEP US SAFE
3Com's security features are on par with other vendors' offerings and include 802.1X, DHCP and ARP snooping, and access control lists, all of which can make unauthorized use of the network and IP address spoofing or theft far more difficult. In addition, the switches have denial-of-service prevention built in to thwart attacks that would overwhelm the switch CPU by dropping frames at the port.

Not all of the security features are available on both the 5500 and 4200 model switches. The 4200 is more of a workgroup device, although some traffic security features, such as DHCP snooping and port privacy--blocking two hosts on the same switch from directly communicating--are available.

The 4200 line doesn't support password policy enforcement, which can be configured to require passwords that contain upper- and lowercase letters, numbers, and symbols. These devices do not support DHCP tracking, which tracks a host's DHCP lease; ARP inspection, which tracks MAC addresses; or IP Source Guard, which ensures that IP addresses can't be taken or forged. If we need these advanced features at the edge, we'll have to upgrade to the 5500g line.