Extreme Networking Achieving Nonstop Network Operation Under Extreme

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Extreme Networking Achieving Nonstop Network Operation Under Extreme Operating Conditions DARPA PI Meeting, July

Extreme Networking Achieving Nonstop Network Operation Under Extreme Operating Conditions DARPA PI Meeting, July 23 -26, 2002 Jon Turner jst@cs. wustl. edu http: //www. arl. wustl. edu/arl

Project Overview n Motivation » data networks have become mission-critical resource » networks often

Project Overview n Motivation » data networks have become mission-critical resource » networks often subject to extreme traffic conditions » need to design networks for worst-case conditions » technology advances making extreme defenses practical n Extreme network services » Lightweight Flow Setup (LFS) » Network Access Service (NAS) » Reserved Tree Service (RTS) n Key router technology components » Super-Scalable Packet Scheduling (SPS) » Dynamic Queues with Auto-aggregation (DQA) » Scalable Distributed Queueing (SDQ) 2 - Jonathan Turner - July 24, 2002

Prototype Extreme Router Field Programmable Port Ext. Control Processor Smart Port Card Sys. FPGA

Prototype Extreme Router Field Programmable Port Ext. Control Processor Smart Port Card Sys. FPGA OPP IPP OPP Pentium APIC IPP North Bridge Switch Fabric OPP 64 MB Cache ATM Switch Core FPX FPX Field Programmable SPC SPC Port Extenders Embedded TI Processors TI Transmisson Interfaces 3 - Jonathan Turner - July 24, 2002 TI FPX SDRAM FPX 128 MB SPC Reprogrammable SPC Application Device TI TI SRAM 4 MB FPX Network SPC Interface Device TI

Resource Reservation in Internet? n Bandwidth reservation can provide dramatically better performance for some

Resource Reservation in Internet? n Bandwidth reservation can provide dramatically better performance for some applications. n Obstacles to resource reservation in Internet. » distaste for signaling protocols » perceived complexity of Int. Serv+RSVP » requires end-to-end deployment » little motivation for service providers n How to get resource reservation in Internet? » keep it simple focus on top priorities - one-way unicast flows n avoid complex signaling - leverage hardware routing mechanisms n » make it useful when only partially deployed » provide motivation for ISPs to deploy it 4 - Jonathan Turner - July 24, 2002

Basic LFS Operation Reserve 8 Mb/s to B Reserve bandwidth A Select best next

Basic LFS Operation Reserve 8 Mb/s to B Reserve bandwidth A Select best next hop n Select path and attempt to reserve 10 Mb/s available 5 Mb/s available 20 Mb/s 5 Mb/s available 2 Mb/s available Complete reservation 20 Mb/s available B Select path and reserve One way, unicast setup with partial reservation. » complete reservations locally when bandwidth released Optional ack returned by far-end access router. n Reservation may terminate explicitly or time out. n May alter reserved bandwidth but no re-routing. n 5 - Jonathan Turner - July 24, 2002

Soft Reservations n Basic LFS provides firm reservations. » user guaranteed bandwidth until releases

Soft Reservations n Basic LFS provides firm reservations. » user guaranteed bandwidth until releases n Can extend to provide soft reservations as well. » soft reservation can be adjusted by the network as traffic changes » can be intermixed with firm reservations to provide a firm minimum, plus more bandwidth as available n Uses of soft reservation. » apps. that need guaranteed minimum and can sometimes use more, but can adjust use to what’s available » more rapidly responding congestion control for traditional best-effort traffic 6 - Jonathan Turner - July 24, 2002

Basic IP Option for LFS n n n Code identifies LFS option. Operations »

Basic IP Option for LFS n n n Code identifies LFS option. Operations » request firm reservation » request soft reservation » release state IP header (fixed part) code Arate Flags » » » sender status request sender network status request public network status request intra-domain status request congested path Rrate: requested rate. Arate: allocated rate. Trace used by each domain to track usage. 7 - Jonathan Turner - July 24, 2002 length op. flags Rrate trace IP payload n n Allocated rate stored at “last hop” router for status generation F. P. rates with 4 bit mantissa, 4 bit exponent. » specify rates from 64 Kb/s to 4 Gb/s , 6% “granularity”

Use of Trace Field acct. record [A, B, . . ] thru X A

Use of Trace Field acct. record [A, B, . . ] thru X A X acct. record [A, B, . . ] thru Z Y domain U X Y domain V Z domain W Z B acct. record [A, B, . . ] thru Y n Network providers need to monitor LFS usage for network management and accounting purposes. » trace field used by ingress router of each domain to mark LFS packets with domain-specific identification » egress router of each domaintains record of each LFS flow, including copy of trace field » end-to-end records created through off-line accounting resolution mechanisms 8 - Jonathan Turner - July 24, 2002

Status Reporting sender status sender net status public net status sender LAN ISP U

Status Reporting sender status sender net status public net status sender LAN ISP U ISP V rcvr. LAN intra-domain status Basic LFS option supports sender status and trace field for accounting. n Network providers likely to want more. n » sender net status allows LFS service verification » public net status allows “end-to-end” status check » intra-domain status for verifying local status » each “extra” status report requires insertion of requestor’s IP address, increasing LFS option length 9 - Jonathan Turner - July 24, 2002

Partial Deployment n Receivers need not be LFS-aware. n Issues with non-contiguous LFS domains.

Partial Deployment n Receivers need not be LFS-aware. n Issues with non-contiguous LFS domains. n No support for non-contiguous LFS domains. » web site may use LFS to reserve bandwidth for streaming media - users benefit, even without LFS-aware hosts » route changes may create “orphan reservations” » no simple way to determine status reporter » LFS router forwarding to a non-LFS router (or host) strips LFS option and implements status reporting n status report includes IP address of reporting router, letting sender know how far the reservation went Public IP carrier can accept LFS option from client networks (LAN) even if client net is not LFS-aware. n Clients may use tunnel to access LFS service. n 10 - Jonathan Turner - July 24, 2002

Regulating LFS Use - Net Access Svc Permitting unconstrained access to LFS creates big

Regulating LFS Use - Net Access Svc Permitting unconstrained access to LFS creates big security vulnerability. n Limit use to authorized users. n Limit number of reservations and amount of reserved bandwidth by authorized users. n » access router keeps record and enforces limits » complication - user may use LFS from multiple locations n n maintain records in distributed set of servers - each server keeps records for some fraction of the users - use hashing to select Access router needs means to identify user. » host IP address insufficient (DHCP, NAT) » encryption-based authentication (IPSEC) Combine access control with usage accounting. n What special issues arise with multiple domains? n 11 - Jonathan Turner - July 24, 2002

LFS Video Demo Configuration video source 100 Mb/s links cross traffic sinks video sink

LFS Video Demo Configuration video source 100 Mb/s links cross traffic sinks video sink cross traffic sources n Wavelet-coded video with and without LFS. » competing datagram traffic » with no reservation, lost packets cause poor video quality » with reservation, high quality preserved 12 - Jonathan Turner - July 24, 2002

Video Demo - No Reservation video flow - no reservation datagram cross traffic flow

Video Demo - No Reservation video flow - no reservation datagram cross traffic flow 1 datagram cross traffic flow 2 video source cross traffic sources 13 - Jonathan Turner - July 24, 2002 all sinks

Video Demo - With Reservation video flow - with reservation datagram cross traffic flow

Video Demo - With Reservation video flow - with reservation datagram cross traffic flow 1 datagram cross traffic flow 2 video sink cross traffic sinks 14 - Jonathan Turner - July 24, 2002

Competing LFS Flows flow 1 - no reservation flow 2 - reservation added flow

Competing LFS Flows flow 1 - no reservation flow 2 - reservation added flow 3 - no reservations reservation for flow 2 sources sink 2 sinks 15 - Jonathan Turner - July 24, 2002 sink 1

Partial Reservation flow 1 - partial reservation made flow 2 source 1 sink 1

Partial Reservation flow 1 - partial reservation made flow 2 source 1 sink 1 16 - Jonathan Turner - July 24, 2002 sink 3

Completing Partial Reservation flow 1 - completes partial reservation flow 2 - drops reservation

Completing Partial Reservation flow 1 - completes partial reservation flow 2 - drops reservation sink 1 sink 3 17 - Jonathan Turner - July 24, 2002

Addition of Flow 3 Reservation flow 3 - adds reservation sink 3 18 -

Addition of Flow 3 Reservation flow 3 - adds reservation sink 3 18 - Jonathan Turner - July 24, 2002 sink 2

Performance of LFS at Single Link Pareto distributed session times make little difference OC-48

Performance of LFS at Single Link Pareto distributed session times make little difference OC-48 link can carry 200 flows of 12 Mb/s very few flows experience any delay n n m = number of flows link can carry exponential session times for flows, infinite queue 19 - Jonathan Turner - July 24, 2002

Sensitivity to Load and Hop Count delay probability scales linearly with number of hops

Sensitivity to Load and Hop Count delay probability scales linearly with number of hops at 90% load, less than 1 flow in 100 delayed more than 12% of session time 20 - Jonathan Turner - July 24, 2002

Overload Performance with no buffer most sessions still succeed with infinite buffer, no sessions

Overload Performance with no buffer most sessions still succeed with infinite buffer, no sessions get small delays (10%) buffer reduces rejection fraction at low loads 21 - Jonathan Turner - July 24, 2002

Summary n LFS provides simple reservations for Qo. S. » no complex signaling, wire

Summary n LFS provides simple reservations for Qo. S. » no complex signaling, wire speed setup » limited deployment can be broadly beneficial » support for usage monitoring & accounting gives network providers a motivation to deploy service n Network access service for regulating usage. » preliminary specification has been developed » uses IPSEC for host/user authentication Performance analysis, simulation study underway. n Routing issues. n » evaluate Qo. S routing with multiple-choice forwarding » link state distribution for inter-domain routing » inter-domain routing policies 22 - Jonathan Turner - July 24, 2002