I was impressed with the number of ports that Atrica could cram into the 1U A-2100. The unit comes with two fiber Gigabit Ethernet ports for connection on the network side. On the user side, the A-2100 has two slots that can be filled with either a single Gigabit Ethernet GBIC or eight 10/100 Ethernet ports. Also available is a 24-port 10/100 card that takes up both slots. The 24-slot Ethernet card is designed for deployment in an environment such as a multitenant office building or an apartment complex. With a four-gigabit backplane, the box can easily handle any traffic thrown at it, as I saw while testing it in Network Computing's Dallas lab.

The A-5100 is an aggregation switch capable of supporting up to 24 Gigabit Ethernet interfaces while fitting into 3U rack space. Twelve interfaces are built-in single-mode modules. The other 12 interfaces can be configured with the GBIC of your choice. Ports can be used in any combination for upstream or downstream connections, which is a little confusing when you think about it.

I connected three A-2100s to a single A-5100 in our lab and used a Smartbits 6000 to generate test unit traffic. Configuration is not difficult. A console port is available on all the units to set the IP address or configure connections manually. As soon as I was sure each unit had an IP address, I was ready to use the NMS (network management software). Atrica's NMS runs on a Sun Solaris server and provides a great graphical interface to the network and connections.

The NMS has three separate server packages -- application, backend and database -- that can run either on the same server for smaller networks or on separate servers for larger networks. The application server acts as the Web server, providing the user interface for configuration and network management. It also handles communications among the user and the backend and database servers. The backend server is the workhorse, building connections among all the devices and pushing network changes to the devices. The database maintains all network configuration and connection data.

Accessing the application server and entering the IP addresses for the four Atrica units was all it took for the server to create a complete network diagram, which I could access through the Web interface. Each Atrica box looks to see what it is connected to and on which port. It then reports that information to the NMS, which in turn draws a graphical representation.

Drag and Drop Networking

Creating connections between endpoints is just as simple. By right-clicking on the A-2100 from which I wanted to create a connection and then selecting "create connection," I was presented with options for creating either a point-to-point or multipoint-to-multipoint connection. The other end(s) is then selected for either choice. Multipoint connections automatically create a fully meshed network between the endpoints. A pop-up list for each device let me choose from ports that have available bandwidth. I also could select whether the connection should have a redundant data link. This provides a failover if something happens to the main fiber connection, keeping customer data flowing uninterrupted over your network. The graphical view shows each connection -- primary and backup -- , allowing me to see how the system would route the traffic.

Connection bandwidth is specified as either CIR (committed information rate) or EIR (excess information rate). These are similar to the SCR (sustained cell rate) and PCR (peak cell rate) of an ATM network. The CIR is set to the guaranteed data rate that you deliver to your customer. The EIR determines the maximum data that will be allowed on the network through a connection. Any traffic above the CIR is marked -- discard eligible -- and dropped if the network is congested. Any traffic above the EIR is automatically dropped. Atrica assumes that providers charge their customers based on provisioned bandwidth, rather than used bandwidth. Right now, there isn't much bandwidth utilization reporting going on -- just the basic stuff. That will change, however, with future updates.

Atrica hasn't overlooked the ability to transport tagged frames, a key issue with so many enterprise customers deploying VLANs within their networks. The company offers two types of VLAN connections, transparent and translation. Transparent connections add a network VLAN tag in front of the customer 802.1Q VLAN identification and then place the tagged data on the network. Translation connections replace specified customer VLAN IDs with 802.1Q network IDs before transporting the data.

I performed basic tests with both units, configuring connections through the network and then adding traffic generated by the Smartbits. I tested each unit on its ability to maintain CIR and EIR data rates. Testing at different values proved that the units police like good cops. I also tested the failover capabilities of the units by disconnecting one end of the main fiber connection and making sure the traffic moved to the backup path. When I reconnected the main fiber connection, the units returned to that path after being up for a few minutes.

I have only two complaints, and both have to do with the software, not the hardware. First, the NMS displays all connections in a list on the left side of the screen. For service providers with large networks, this creates a long list that must be scrolled through. It would be nice if the list could be broken down by customers, PoPs or some other determinant such as customer number. This would make it faster and easier to find a connection. My second complaint is that data rates are synchronous; both directions have the same CIR and EIR. Some customers may find it easier to use asynchronous data rates that allow different bandwidths for each traffic flow direction.

Overall, both the A-2100 and A-5100 work as advertised. Atrica promises to add features, such as asynchronous bandwidth creation, in upcoming software releases and, indeed, both switches have room to grow. Still, what the company offers in its first release will satisfy the needs of most MAN network installations.

Darrin Woods is a technology editor of Network Computing. Prior to joining the magazine, Darrin worked as a WAN engineer for a telecom carrier. Send your comments on this article to him at dwoods@nwc.com.