Testing Cisco-Linksys Switch for IP Video (SRW208P)By Benros Emata, Published Aug 31, 2010, 12:00am EDT
Switch selection for IP video surveillance is a key consideration in overall design. Unfortunately, it is often less scrutinized than the 'stars' of the solution (i.e., VMS and cameras). Moreover, sufficient due diligence in evaluating switches may not be performed due to difficulty of making sense of the technology, offerings, and application. End-users should pay closer attention to the networking devices they purchase since they can have a significant impact on the availability and quality of the system.
In this report we test a Cisco-Linksys SRW208P small business class managed switch we purchased from Amazon. The SRW series provides managed small business class switches, featuring a variety of PoE enabled fixed configuration options targeted for 'budget' or inexpensive applications.
The video below provides an overview of the test:
The Cisco SRW208P is an economical option for video surveillance applications. The SRW is the lowest priced fully managed switch family supporting PoE in the Cisco SMB switch portfolio.
The switch performed with no discernable issues when loaded with multiple megapixel cameras. Also, there appeared to be no issues powering multiple PoE cameras simultaneously from the switch. We found the internal monitoring of individual interface bandwidth utilizations and individual port PoE power utilizations, to be thoughtful inclusions. These monitoring features are accessed directly from the browser based GUI, called WebView.
The browser based WebView configuration interface was straight-forward and intuitive for basic configurations, but was confusing for the more advanced configurations such as VLAN, Trunking, Link Aggregation, Multicast, Quality of Service etc. The included documentation CD/PDF seemed to provide inadequate coverage and background for advanced configurations. The documentation would benefit from more in-depth treatment, example configurations and diagrams for the more advanced applications. We had to inconveniently search through the support site to accomplish more complex tasks.
In our tests, we performed a limited number of open standards based integrations with third-party devices/systems. We successfully integrated the switch with an enterprise class Cisco Catalyst switch by connecting the two via an 802.1Q trunk. We also were able to communicate between separate VLANs on the switch using the routing properties of the enterprise switch. We also tested SNMP by configuring a third-party monitoring tool to poll interface bandwidth utilizations from the SRW208P. We were not able to find support to poll CPU utilization from the switch, however.
We recommend using this switch in stand-alone 4 to 24 camera systems, where PoE, and low to high bandwidth SD or megapixel cameras are used. This product is also suited for systems requiring smaller campus-like network topologies, as it supports (2) fiber-based Gigabit Ethernet ports.
While we did perform a few open standards based integrations with a representative enterprise switch, we would approach using this switch in a corporate network cautiously. Larger corporate networks may object to a non-enterprise class switch 'touching' their network, especially without a requisite level of interoperability testing.
Despite manufacturer claims and specifications of many supported open networking standards, deployments dependent on integration with other vendor or even other families within vendors should be adequately tested to confirm interoperability levels.
A proof of concept test should be performed for systems requiring other advanced networking functionality such as multicast, STP, and QoS.
The Cisco SRW208P provides 8 Fast Ethernet PoE ports and 2 Gigabit Ethernet Combo ports. The switch provides 80Watts of total PoE power across Fast Ethernet interfaces. It supports up to (8) class II 7.5W and (4) class III 15.4W PoE devices.
The SRW supports a large set of features expected of managed switches, such as VLANs, SNMP, STP, RSTP, MST, 802.1Q trunking, IGMP snooping, port security, port mirroring, 802.1x/Radius etc.
The SRW family includes many models with (2) and (4) Gigabit Ethernet interfaces to allow for campus-like topologies up to 10km.
Cisco's unmanaged series of switches provide little to no support for PoE, which makes little sense for today's PoE enabled IP camera market. Lack of PoE support in the unmanaged switch families can be overcome with mid-span PoE injectors. However, the addition of a mid-span PoE injector adds substantial cost to the deployment and negates any cost benefit gained by opting for the unmanaged switch. Indeed, a Google price search on 8-port mid-span PoE injectors yields a range of approximately $200 - $500 - online pricing for the featured SRW208P is around $275. Generally, unmanaged switches are a poor option due to the lack of visibility one has into the switch's quality of operation, performance and availability.
Among the Cisco managed SMB switches the SRW, SLM, SFE/SGE, ESW500 and 2960/2960s series SMB switches offer features fitting for IP cameras at a reasonable price point. The 2960s series is currently the most cost effective Cisco option for deploying PoE+ or 802.3at enabled devices.
Online pricing for the SRW208P is approximately $275. This amounts to $35 per camera. In contrast a mid-market enterprise class Cisco 3560-8PC switch for $900 would cost $113 per camera - a $78 per camera difference. In a hypothetical 32 camera installation requiring 4 units of 8-port PoE switches across a multi-floor or campus scenario, opting for the higher-end switch would cost $2500 more than the SRW208P. When considering deployments requiring connectivity beyond the 100 meter limit of 100BaseTX Fast Ethernet, note that the SRW208P supports 2 fiber optic ports and the Cisco 3560-PC only supports 1 fiber optic port. Having only 1 fiber-optic port limits the supported deployment scenarios.
Furthermore, SFP or mini-GBIC modules for enterprise and SMB networking gear are priced differently by Cisco. The result is a near 4x premium paid for fiber-optic modules that do essentially the same thing. Here's an example of the most expensive module from each class supporting gigabit speeds over single-mode fiber to distances of 10km:
- Cisco SMB Switches: MGBLH1 - List $246
- Cisco Enterprise Switches: GLC-LH-SM - List Price $995
The price difference narrows or practically disappears if you opt for 3rd party SFP and mini-GBIC modules. However, be aware of potential compatibility, warranty and tech support issues when considering 3rd party modules.
Potential users of this switch might falsely assume that because it carries the 'Linksys' name or that its configuration is GUI driven, it might be easier to configure advanced features such as Quality of Service, Link Aggregation, or multicast. This is hardly the case. Nowhere on the SRW208P product page is the product said to be 'easy' to configure. Cisco is positioning this switch as a fully managed, affordable, and future-proofed product.
We did not perform tests on advanced networking services such as QoS, Multicast, and STP. These features are, generally, not required in small scale video surveillance applications. Therefore in the smaller systems for which this switch is recommended, the risk of these services not functioning is eliminated. Conversely, situations that require the implementation of advanced networking services and higher levels of cross-vendor interoperability should be adequately tested to ensure operation in more demanding environments.
Though the SRW family is a managed group of switches, we still suspect that enterprise network admins or IT staff may eschew the integration of these 'odd-ball' switches into their networks. Corporate IT departments have many well-founded reasons to maintain as homogeneous a network as possible. These policies reduce risk of interoperability issues between devices, help assure that new devices are supported by network wide monitoring and management systems, and capitalize on existing knowledge and familiarity with products, by avoiding training for new systems or products.
In this video, we provide a look at the physical characteristics of the SRW208P, show the accessories that come in the package, and demonstrate an example of the mini-GBIC ports for optical connectivity. Traditional security integrators have shown confusion over the use of uplink ports. Essentially these ports are the same as the regular (access) ports on a switch, but because of higher speeds are usually used to uplink to another switch for aggregation or backhaul purposes. There's no reason you can't plug IP phones, VMS servers, access-points, IP cameras and other end-points into these ports. The one caveat is that uplink ports typically don't support PoE.
- Eight (8) 10/100 PoE enabled Fast Ethernet interfaces
- 2 Combo Gigabit Ethernet Uplink Ports
- A console or serial port for direct administration; serial cable included
- An included 19" rack mounting kit
- A documentation CD
- Fan operation
- AC adapter with 12 feet of cabling length
Administration and Configuration
In this screencast, we examine basic configurations necessary to manage your switch both locally and remotely. We then, 'walk-through' the browser based set-up screens that Cisco calls WebView, and focus on some key features. You will witness the switch's internal monitoring capability that allows a user to view 15 second averages of interface BW utilization and exact milliwatts being consumed by PoE enabled devices. We'll contrast the internal monitoring with the highly detailed monitoring provided by PRTG, a third party tool. Finally, we perform a simple VLAN configuration and demonstrate an integration between the SRW series switch and an enterprise level Cisco Catalyst switch.
In this screencast, we demonstrate the use of the SRW208P in a specific design application - a 3 story building with 24 megapixel cameras. We then extend the functionality of the switch to connect 2 more satellite offices in a campus environment using fiber based Gigabit Ethernet. The network design principles that we illustrate can be applied to many other video surveillance applications. We'll, also briefly explore fiber-based Gigabit Ethernet standards. See here for Cisco's mini-GBIC application brief and also their SMB mini-GBIC datasheet.
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