3com 5500-SI Manual Do Utilizador

C

HAPTER

 1: G

ETTING

 S

TARTED

The Switch 5500 family

 supports the following services:

■

Internet broadband access

■

MAN (metropolitan area network), enterprise/campus networking

■

Multicast service, multicast routing, and audio and video multicast service.

With the XRN (eXpandable Resilient Networking) feature, you can connect several 
devices into a combined device and manage them as a single unit. The combined 
device is called the Fabric, while the member devices are units. With XRN you can:

■

Manage multiple devices in centralized manner, with low management cost. 

■

Extend the number of ports and switching capacity just by adding devices. You can 
decide which equipment to purchase as needed, and better protect your existing 
investment while upgrading the network.

■

Provide backup between multiple devices to improve reliability and to eliminate 
single points of failure.

XRN includes three technologies: distributed device management (DDM), distributed 
link aggregation (DLA), and distributed resilient route (DRR).

■

DDM: Users can treat the Fabric as a single device. They can manage the Fabric 
through any port or IP address connected into the Fabric, and from any unit in the 
fabric.

■

DRR: The multiple units of a Fabric route and forward packets as a single unit, and 
provide uniform VLAN interfaces, routing table and L3 forwarding table, so the 
Fabric is regarded as a single Layer 3 switch. Failure of one of the units will not 
affect routing protocol and data forwarding.

■

DLA: Users can aggregate multiple ports of several different units in a Fabric into a 
group, for centralized management within the Fabric. Trans-unit link aggregation 
can bring convenient aggregation setting and effectively reduce single points of 
failure.

Typical XRN networking topology is as shown in Figure 1. Switches of the same type 
(that is, units) form a Fabric. As a core switch, the Fabric can be downlinked to 
workgroup switches through several aggregation links, and uplinked to the server 
group also through several aggregation links.

5500G-EI 
PWR 48-Port

AC-input, 
DC-input

48

—

44 10/100/1000 
Mbps plus 4 
10/100/1000 or SFP

1

5500G-EI 
24-Port SFP

AC-input, 
DC-input

24

—

20 10/100/1000 
Mbps plus 4 
10/100/1000 or SFP

1

Table 3   Models in the Switch 5500 family (continued)