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2008.02.20 NANOG 42 current state of 10gig pluggable technologies
Continuing on with the notes from this morning's talks, pushing out the notes while we take a bit of a break. :) Matt 2008.02.20 10 gig pluggable technology Richard A Steenbergen from nlayer [email protected] Many thanks to Todd for donation of the slideset! Title is 10gig, but it applies to other technologies as well; fiberchannel, etc. What are pluggables? transcievers you plug into your router or switch, they can drive multiple media types (copper, fiber, short reach, long reach, etc) There's standardization among the parts, so that vendors can use common parts. technical benefits, you can mix-and-match media types on the same router/switch card; easier replacement in the event of optical failure. financial benefit--pay as you populate. reusable, easily re-deployable elsewhere cards are reusable as technology evolves; can migrate from fiber to copper easily. standardization lowers costs. standardized, allows for interoperability standardized via vendor MSA (multiple source agreement) specs published under SFF, which defines the strict specs to be followed. First gen pluggable technology; started in ethernet land with GBIC, first came from the fiberchannel world; commonly in use from 1998 to 2002. >From 2002 onward, started shifting to sfp form factor; multirate, so you can use same pluggable for 1g, 2g, 4g fiberchannel, can use for gig or OC48 SONET First introduced digital optical monitoring (DOM) in 2004. better density. 1g to 2.5g, had GBIC and SFP. For 10G, many, many choices (7) 300-pin XENPAK XPAK X2 XFP ... Problem in operator community now is that with so many options, sparing is hard. slide with overall size comparisons. First 10G was 300-pin MSA; not pluggable, but a snap-on connector; 8-14W, 16x622Mbps interface. Same thing used for 40G XENPAK MSA, march 2001, second most popular at this point. power 6-10W XAUI (4x3.125G) PHY framer onboard 80km+ ZR, DWDM tuned, other exotic optics X2 MSA, July 2002 same electrical as Xenpak 4-5W, rest is same as xenpak, just smaller. Cisco and HP are only users of it; lukewarm support for it. very few exotic optics choices for it. XPAK MSA similar to X2, XAUI interface uses LC connector, different form factor, for use on PCI cards no exotic optics not used in network world. XFP MSA, march 2002 XFI (9.995-11.1G serial interface) variable speed serial interface PHY framer is offloaded; can be 10G, OC192, transport, etc. One of most commonly deployed optics exotic: ZR/DWDM, limited CX4, no LX4 very, very popular eliminating serdes for 10GBASE-RW is big power saver power 1.5-3.5W SFP+ MSA draft dec 2007 interface SFI (8.5 - 11.1G) same dimensions as SFP, same connector extend down to do 8G fiberchannel PHY framer offloaded no exotic optics smaller than XFP, offloads CDR function SFI similar to XFI, adds 8G FC speed limited power use power 1-1.5W 10gig pluggable component technology PHY, physical layer component PCS --physical coding sublayer PMA physical medium attachment sublayer serdes CDR clocking data recovery chip 10gig PHY comes in 3 variants 10GBASE-R LAN 10GBASE-W WAN similar to R, but wrapped in OC192 SONET compatible frame 10GBASE-X Lan phy 4x2.5G parallel signal LX4 is 4 optical channels, mux built in CX4 is 4 copper channels same choices for interconnect; XAUI is 4x3.125G parallel channels (8B/10B encoding) XFI/SFI, single 10gig serial channel uses 64B/66B, much more efficient encoding each time you convert, it increases heat, power, consumes port space, etc. Ultimate goal is to match technologies; if you have 4 parallel lanes on each side better XAUI to 10GBASE-X XFI/SFI to 10GBASE-R/W So XAUI to 10GBASE-R, inefficient XENPAK has room for serdes stages, fortunately Future directions for technology? new technogies replace old 10GBASE-LRM long reach multimode replaces LX4 10GBASE-T to replace old CX4 for copper uses standard cat6/cat7, 8p8c (RJ45) connectors Advantages of offloading PHY framer can use same pluggable for multiple protocols allows better component reuse, lowers costs can use in transport gear with forward error correction 10GE WAN PHY much bette when done on host can use any PMD without having to buy special pluggables improves sparing, lowers costs, expands PMD options improves WAN layer control signalling and alarms provides access to SONET alarms, path trace, etc. vastly improves troubleshooting with OC192 carriers Advantages of offloading the CDR make pluggable smaller, uses less power disadvantages mostly zero sum gain; no components saved, just moved to board not all CDRs are created equal may want higher quality on longer runs can't upgrade pluggable to get better EDC (electronic disperson compensation) technology Evolution of pluggable power use (watts) power consumption going down over time; different classes of power use. Not only dropping power, but removing entire power classes. comparison chart of optics slide. Software side of pluggables talk to host via low speed control bus; power down, alarm signalling, etc. Digital Optical Monitoring lets you see power levels on the link, speeds up troubleshooting. TDR functionality for copper hosts can also read EEPROM data allows vendors to lock users into particular pluggable. Vendors don't make their own pluggables, they're made by JDS Uniphase, finisar, hitachi, etc. pluggable has EEPROM, set vendor string $1.4B in profit at Cisco from reselling pluggable optics. how keep customers locked in: FUD (won't support it, might blow up, support contract is void, etc.) financial component; many sellers, few buyers; if Cisco controls 70% of market, they can set the prices, and prevent them from being resold outside their channel. Vendor locking--if it's not ours, router won't support it. Big customers are pushing back on that. counterfiting cisco is now the new way to make money, as you make profit by charging for name. new model is doing feature impairment; certain features like DOM are set so that it's only usable with their own pluggable. What format is right for you? XENPAK has best selection, well stocked, most exotic optics options downside; very large, draws a lot of power, not protocol agnostic, not friendly with WAN PHY X2--smaller than xenpak, lower power allows for higher density full support for LX4/CX4, pushed by cisco very little deployed base, few sources, few exotic optics same as XENPAK, not protocol agnostic XFP--advantages--large deployed base, cheap, easy to find, technologies still being upgraded on it. power/density pretty good for most users. protocol agnostic, easy spare, good WAN PHY cheapest option for long reach/DWDM SFP+ -- very high density (48 per blade) physically same as SFP may allow for extremely low cost device (GoogleSwitch) downside; hard cutoff on power budget, hard to do longer reach optics; no DWDM, no LR, no ZR; won't ever be able to be full replacement for XFP because of that.