Setup and Configuration - more
Like both the D-Link and the Linksys managed switches, the SLM2008 supports 802.1x security. When enabled, clients have to authenticate to an external RADIUS server in order to be granted access to the network. The SLM2008 also supports Static MAC addresses. If enabled, only MAC addresses associated with specific ports will be allowed access to the network. These are some of the features that distinguish the SLM2008 from the Dell 2708 8-port smart switch.
The SLM2008 does support QoS (Quality of Service), but the configuration options are limited. You have a choice of Port based, 802.1p, or DSCP (Differentiated Services Code Point). For both port based and 802.1p, you can assign either the port or 802.1p value to one of four QoS queues. For DSCP mode, you can map an individual value to the high, medium and normal queues. All other DSCP values are automatically assigned low priority.
For queue modes, the SLM supports Strict priority or WWR (weighted round robin) with your choice of eleven WWR weighting rations. Though this is a fair amount of control, the SRW2008 provides even more control with bandwidth shaping, choice of trust mode, individual DSCP value mapping to queues, and mapping Class of Service (COS) to queues.
Figure 6: QoS WRR setting
Another feature that differentiates the SLM2008 from the Dell 2708 is support for Spanning Tree. Though the configuration options are very limited compared to the SRW2008, you can define path cost (auto default), system priority, Hello time, Max Age and Forward Delay.
One of the surprising omissions on the SLM2008 is the lack of support for SNMP (any version), RMON, or any logging. There are basic per port statistics for frames/bytes sent and received, TX/RX errors and TX/RX broadcasts, as well as IGMP status, but that’s about it.
I find it quite curious that the switch would support enterprise features like 802.1x, Spanning Tree, and QoS, but fail to include SNMP support. While in many SOHO environments lack of SNMP support would not be a liability, larger organizations with fully managed networks would likely reject the SLM2008 as a workgroup switch in favor of a switch with the capabilities of the SRW2008.
Tim used the SLM2008 for his investigation into the effect of flow control in mixed gigabit / 100 Mbps LANs (When Flow Control is not a Good Thing) and found its performance to be the same as any other gigabit switch. Once again, these are devices that you buy based on supported features and not performance differences.
Linksys’ marketing says that their smart switches offer entry-level management without the cost and complexity of a full Layer 2 managed switch. I have to agree—at its price point, it offers many more features than even the Dell 2708, yet is still fairly easy to configure. An online help system such as is found in its fully managed SRW2008 sibling would be a welcome upgrade, as would support for SNMP. However, if you need an 8-port gigabit smart switch, the SLM2008 is a great choice.