Gullik Webjörn Gigabit Ethernet 1 of 17 Terena Summer 1999

Session Overview  What is Gigabit Ethernet ? –Technology –Media  Gigabit Ethernet Applications –Computer rooms –Server farms –Cluster  Problems and Solutions Gigabit Ethernet –DMD, differential mode delay –Collision domains 2 of 17

What is Gigabit Ethernet?  Ethernet with a speed of 1 Gbit/sek. –IEEE 802.3z –Both CSMA/CD and Full Duplex –Both fiber and copper ( Fiber Channel, 8b/10b ) –Follows the same development rate as 100 Mbit Ethernet but converges much faster.  Suggested ‘improvements’ and adaptions –Jumbo Frames ( 9K bytes ) –VLAN –Protocol stack parameter modifications. 3 of 17

1000baseFiber  Multimode fiber, both 50/125 och 62/125. –Installed fiber in buildings and campuses –850 nM = 1000base SX, m (cost) –1300nM = 1000baseLX, 550 m (distance)  Singlemode fiber 9/125 –Metropolitan networks and large campus net’s –5000 m with 1000baseLX optics –10000 m with “hot optics” –80000 m with “proprietary optics” 4 of 17

1000baseCopper  STP / Coax baseCX z –25 m over ohm pairs / 2 75 ohm Coaxes –Relatively low cost and simple –Preferably in the Computer Room –8b/10b coding and simple transmission at 1250 baud  Cat 5 UTP baseT ab –100 m and uses all 4 pairs –Complicated technology, DSP, PAM-5, FEC –Most standardized copper media –250 Mbit / 125 Mbaud * 4 par 5 of 17

Problems and Solutions, GBE  Pure scaling of Ethernet to 1 Gbit –Slottime becomes 512 nS –Max network diameter becomes m –Hard to achieve efficiency at half duplex  Increased slot-time –4 uSek slot-time creates 200m collision domain –Packet bursting increases efficiency  Full Duplex –Limited only by transmission characteristics –Capacity = 2 * half duplex –Wire-speed now becomes realistic 6 of 17

Problems and Solutions, GBE  DMD, differential mode delay –In multi-mode fiber discrete modes can dominate –The problem increases with shorter wavelength –The problem increases with better coherence –Worst at 850 nM and 62/125 fiber –Reduces distance due to jitter and ISI  But, the problem might be overrated... –802.3z June 98 meeting –1000baseSX gets reduced distance (220/62/160) –1000baseLX gets 550 m over all MMF –1000baseLX increased from 3 to 5 km over SMF 7 of 17

Full Duplex and Switching  More common than CSMA/CD 1998 already –The arbitration problem goes away. –Suitable for silicon based switches and routers –Greater freedom to choose topology –At least twice the performance of half duplex –Possibility to switch ‘cut-through’ –Enables clusters with low latency and high bandwidth. –Full duplex is available today –NO more HUBS! 8 of 17

Synergy effects  Disks and Networks –Both based on “fiber channel” –Server area networks Mbyte/sec FDX –Storage networks -- U-SCSI and GBE –Common components results in a nice price/performance improvement (GBIC, t.ex.)  Metropolitan Networks –The technology with best price/performance –10000’s of users at 100 kbit/sec –100’s concurrent MPEG-2 video streams –Makes multicast video possible (BC IP/TV) 9 of 17

Adapters and Server performance  Gigabit adapters need bus bandwidth –64 bit (and 66 Mhz ) PCI –Proprietary busses of abt. 200 Mbytes/sek –1518 bytes is too short a packetlength –A full 1518 bytes = packets/sec/HDX  Performance examples –High end Intel server std stack Mbit/sec  Tested in house with 4 clients. –Alpha Server Mbit/sec –Alpha Server using Driver API - wire speed  Your mileage will vary !!! 10 of 17

Cluster and Gigabit Ethernet  Redundant PHY -- media fault tolerance Need or wish... Available over FDDI but not over Fast Ethernet Available in switches, when do we get a NIC ?  Jumbo frames -- storage transport efficiency Ethernet and Fast Ethernet 1500 bytes FDDI bytes GBE bytes  Cut through -- Lock management efficiency Efficient lock mgmt with large # of nodes. 11 of 17

Quality of Service  As for other technologies: in the network boxes –Not a specific characteristic of GBE –High bandwidth reduces the need –IEEE 802.1p and 802.1Q - frame tagging –Networks have barely caught up with CPU’s  Common with level 2,3,4 switching in GBE-switches. –Not really QOS –Allows priority for time critical services –Or, you can route such traffic a different path 12 of 17

Present and Future  Hunt groups –2-many aggregated links –Redundancy, multi links - single logical port  10 Gbit Ethernet –2.5 Gbit single pipe –4 * 2.5 Gbit / sec WDM –10 Gbit single pipe  Aggressive cost curve projections –Shared Gigabit -- $450 - $700 per port (NOT !) –Switched Gigabit -- $ $1600 per port (!!) –All switch or nic functions on single CMOS ASIC 13 of 17

Present and Future  1550 nM GBIC’s – km on single mode fiber –Will fit almost any GBE box with modular phy  GBIC’s are getting cheap... –850 nm at $ 300 list –1300 nm at $ 900 list –Fixed optics is going away…..  VLAN is going WAN – p and Q over packet over SONET – SONET/SDH is no more “the only way” – Black colors are coming…with optical muxes 14 of 17

Compaq SW54xx Gigabit Products Policy-Based QoS Layer-3 IP Routing (RIP, RIP2, OSPF) 256 VLANs per switch 802.1p and Q 128,000 MAC addresses Port bonding (4 ports) SW /100 Base-TX and 6 Gigabit SX Ports SW /100 Base-TX and 3 Gigabit GBIC Ports with 1 redundant phy SW Gigabit SX and 2 GBIC Ports SW /100 Base-TX and 2 Gigabit GBIC Ports with 2 redundant phys SW /100 Base-TX and 1 Gigabit GBIC Port with 1 redundant phy Features:

 Backbone Layer 2/3/4 switching  8 slot chassis (16 slot coming soon) – Over 30 Gb/s switching throughput – Gigabit Ethernet and Fast Ethernet connections via modules – Future WAN interface modules  Deploy as a backbone interconnection between switches and as a connection to high-performance servers.  Industrial-strength, GIGAswitch-class performance and reliability for high-speed backbones. GIGAswitch/Router GIGAswitch/Router

 Independently Verified – 16 Gbps, 15 Million pps  56 10/100 ports  14 Gigabit ports  Future Support for ATM, FDDI, SONET, WAN  Independently Verified – 32Gbps, 30 Million pps  /100 ports  30 Gigabit ports  Future Support for ATM, FDDI, SONET, WAN Two GIGAswitch/Router Chassis 8-Slot Chassis 16-Slot Chassis

Compaq Computer Corporation © 1999