On Fri, Sep 24, 2010 at 03:52:22PM +0530, Venkatesh Sriram wrote:
Hi,
Can somebody educate me on (or pass some pointers) what differentiates a router operating and optimized for data centers versus, say a router work in the metro ethernet space? What is it thats required for routers operating in data centers? High throughput, what else?
A "datacenter router" is a box which falls into a particular market segment, characterized by extremely low cost, low latency, and high density ethernet-centric boxes, at the expense of "advanced" features typically found in more traditional routers. For example, these boxes tend to lack any support for non-ethernet interfaces, MPLS, advanced VLAN tag manipulation, advanced packet filters, and many have limited FIB sizes. These days it also tends to mean you'll be getting a box with only (or mostly) SFP+ interfaces, which are cheaper and easier to do high density 10GE with, but at the expense of "long reach" optic availability. A "metro ethernet" box also implies a particular market segment, typically a smaller box (1-2U) that has certain advanced features which are typically not found in other "small" boxes. Specifically, you're likely to see advanced VLAN tag manipulation and stacking capabilities, MPLS support for doing pseudowire/vpn PE termination, etc, that you might normally only expect to see on a large carrier-class router. Also, an interesting side-effect of the quest for high density 10GE at low prices is that modern datacenter routers are largely built on third party "commodity" silicon rather than the traditional in-house ASIC designs. Many of the major router vendors (Cisco, Juniper, Foundry, Force10, etc) are currently producing "datacenter routers" which are actually just their software (or worse, someone else's software with a little search and replace action on a few strings) wrapped around third party ASICs (EZchip, Marvell, Broadcom, Fulcrum, etc). These boxes can definitely offer some excellent price/performance numbers, but one unfortunate side effect is that many (actually, most) of these chips have not been fully baked by the years of experience the more traditional router vendors have developed. Many of them have some very VERY serious design flaws, causing everything from preventing them from fully implementing some of the features you would normally except from a quality rouer (multi-label stack MPLS, routed vlan interface counters, proper control-plane DoS filter/policing capabilities, etc), or worse (in some cases, much, much worse). YYMV, but the 30 second summary is that many vendors consider "datacenter" users and/or use cases to be unsophisticated, and they're hoping you won't notice or care about some of these serious design flaws, just the price per port. Depending on your application, that may or may not be true. :) -- Richard A Steenbergen <ras@e-gerbil.net> http://www.e-gerbil.net/ras GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)