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Premium Network, Four Ways
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March 21, 2003
By Peter Morrissey
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To help you cover all the bases in a network infrastructure buildout or redesign, we created a fictional insurance company, CradletoGrave, outfitted it with pie-in-the-sky plans, and issued an RFI to Alcatel, Allied Telesyn, Cisco Systems, Enterasys Networks, Extreme Networks, Foundry Networks and Nortel Networks.
C2G's new network will span four buildings in an office park and one remote location connected via a 45-Mbps WAN link. The company has more than 1,100 desktops and 12 high-end servers, with plenty of fiber connecting the buildings on its main campus. It's seeking Gigabit Ethernet connections to each building as well as two 10 Gigabit ports on the backbone switch/router to accommodate growth in one of the external buildings. C2G runs critical ERP (enterprise resource planning) applications and is considering adding VoIP (voice over IP) and a wireless LAN. We designed our RFI to obtain information on the vendors' ability to deliver a high-availability, redundant, high-speed network with support for VoIP via QoS (Quality of Service) and PoE (Power over Ethernet). For more details, see "CradletoGrave Looks To Grow."
Nortel never responded to our invitation, and Cisco declined to participate. Allied Telesyn's response did not qualify because the company did not adhere to our requested format and offered no 10 Gigabit capabilities.
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Those vendors that stepped up with qualified responses--Alcatel, Enterasys, Extreme and Foundry--impressed us, proving that at least four major networking vendors can deliver robust, manageable, end-to-end switching and routing connectivity from the wiring closet to the core, over the LAN and over the WAN. We've put the complete RFI as well as detailed responses online. The level of detail was high--the vendors provided more information than we could fit in print--and we recommend that anyone considering a major infrastructure purchase take a look.
Keep It Basic
For our C2G scenario, we stuck with switching and routing because it would have been difficult for our target vendors to do soup-to-nuts proposals. For example, Alcatel has a very good VoIP system, and Enterasys is a player in the wireless market, but neither does both. So, we indicated in our RFI that we wanted C2G's network to be ready for both VoIP and wireless, thus keeping our options open and not giving any vendor an advantage based on specialized offerings. It's the best of both worlds in that we were able to consider Alcatel for VoIP no matter whose switching and routing we chose (though, if C2G did give the bid to Alcatel, it would have an edge).
As for PoE, the estimate is that 802.3af will be finalized around June. Companies that are ready now will see that Foundry and Enterasys came up with nice compromises by partnering with vendors that provide external equipment for adding power. These "midspan" devices introduce power into a desktop connection by tapping into the cable. Note, however, that this solution is not a panacea: The devices take up space, are additional points of failure and generally add complexity to the network. For now, when purchasing any PoE-related products, insist they be guaranteed to support the final standard.
On the bright side, support for other standards that enable VoIP and wireless technologies is consistently good. In the case of QoS, which is essential for a successful VoIP implementation, not only are standards like DiffServ and 802.1p there, the implementations are mature. For example, all the vendors support features that make it possible to maintain Layer 2 QoS settings (802.1p) through a router, which can sometimes be problematic because routers strip off Layer 2 frames and thus lose initial Layer 2 priority settings (which means there won't be any prioritization if the frame encounters Layer 2 switching after going through a router). Most VoIP-phone vendors will turn on Layer 2 and Layer 3 QoS, and all the vendors can rebuild Layer 2 QoS settings as frames emerge from the router based on Layer 3 QoS settings.
All the vendors can police QoS settings and reset them based on factors such as VLAN and IP address. And they can do all this magic in ASICs--read: at or close to true wire speed.
We were surprised to learn from our reader poll that only 8 percent of you are using DiffServ or its equivalent, ToS (Type of Service), for marking priorities at Layer 3. However, 15 percent of you plan to do this by year's end. A much larger number of you prioritize packets based on TCP or UDP ports (33 percent) or by IP address (again, 33 percent), and more of you plan to do so in 2003. You'll be glad to know that all four vendors claimed to have this capability, as well as many variations, all done in ASICs.
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