Technology and Administrative Coordination Issues

Pacific Rim Networking WorkshopGuy Almes <almes@internet2.edu>

Manoa Valley, Oahu22 February 2002

Internet2 Engineering Objectives

Provide our universities with superlative networking: Performance

Functionality

Understanding

Make superlative networking strategic for university research and education

Technology Issues

Multicast

IPv6

Performance

Measurement

Security

Multicast

Any Source (Conventional) IPv4 Multicast Steve Deering's PhD thesis from Stanford

Led to MBONE, then native IP multicast

PIM-Sparse, MBGP, and MSDP

Technical Implications Group g has global significance

Host s creates and joins g and can both send and receive packets

Other hosts can join g and can both send and receive packets

MSDP needed to discover the source(s) sending to g

Each host receives packets from <*,g>

Issue: Global deployment

Careful inclusion of ASM IPv4 Multicast in international peering

Inclusion of multicast issues on local campuses

Bandwidth must be sufficient for all sources to all destinations

Allocation of group IDs

Issue: Multicast Applications

Access Grid and DVTS: distance education and conferencing among sets of collaborators

Streaming Audio/Video

Sending files to many destinations, as with Digital Fountain

Issue: Scalability and SSM

Recall implications of ASM Global Significance of 'g' value

Any host can join/send to group g

SSM being deployed to resolve this Host s creates a channel <s,g>

Others can subscribe to <s,g>, but only s sends

Source discovery now trivial, so MSDP not needed

g now only has local significance

Easy to support in wide area, but new IGMP needed Applications need to be adapted

IPv6

Clarify motivation for IPv6 End-to-end transparency and global addressability

Supports application innovation, e.g., peer-to-peer

Support deployment and engineering expertise on networks, especially on campus

Anticipate need for first-class support E.g., 10 Gb/s Abilene upgrade

E.g., Linux, Windows XP

Issues: Training

Within Internet2, IPv6 Training Workshops About 8-10 workshops this year

First: in Los Angeles, hosted by CENIC, in February

Issue: Deployment

Get some IPv6 on each campus/NRN Tunneled IPv6 over IPv4 works well

Performance and network management are limited, however

Prepare for native peering Abilene will be native IPv6 as part of current upgrade

Implications for router selection!

Explore applications, DNS, operational stability, multicast

Issue: Performance

Tunnels limit performance dramatically About 30 Mb/s on Cisco 7200, for example

Some tunnels will exist for some time

But, we must remove tunnels in all performance-sensitive paths

Thus, remove tunnels from key wide-area connections

Issue: Operations

IPv6 needs to become a 'normal' protocol

Robustness of DNS etc.

Mature network management etc.

End-to-End Performance:Bandwidth

In former times, very low bandwidth led to (correctly) low expectations

Now, serious bandwidth exists TransPac deployment of two OC-12 representative

Bandwidth growth will likely continue North America to Europe as a challenging example

End-to-End Performance: Latency

Bandwidth is not the only issue Neither the speed of light nor

geographical distance across the Pacific have improved!

Thus, round-trip times cause problems: Sluggish TCP convergence

Interactive applications more difficult

Thus, direct physical paths needed Hawaii can play a role here

End-to-End Performance: Packet Loss

TCP Throughput MTU / (RTT * PacketLoss)

This packet loss include that due to: Congestion

Other sources

Thus, we need to remove any source of non-congestive packet loss

End-to-End Performance: MTU

There is almost always an Ethernet link somewhere along a wide-area path, hence end-to-end MTU seldom more than 1500

But larger MTUs are supported on wide-area links, e.g., 9180 on Abilene

When performance really matters, work to support large end-to-end MTUs

Threats toEnd to End Performance

Fiber problems dirty fiber

dim lighting

'not quite right' connectors

Threats toEnd to End Performance

Fiber problems

Switches horsepower

full vs half-duplex

head-of-line blocking

Threats toEnd to End Performance

Fiber problems Switches

Inadvertently stingy provisioning mostly communication

happens also in international settings

Threats toEnd to End Performance

Fiber problems Switches Inadvertently stingy provisioning

Wrong Routing asymmetric

best use of Internet2

distance

Threats toEnd to End Performance

Fiber problems Switches Inadvertently stingy provisioning Wrong Routing

Host issuesNIC

OS / TCP stack

CPU

Perverse Result

'Users' think the network is congested or that the Internet2 infrastructure cannot help them

'Planners' think the network is underutilized, no further investment needed, or that users don't need high performance networks

Measurements

Traffic utilization MRTG, etc., need to be more visible

Performance-related measurements iperf, AMP, Surveyor, etc. along key paths

Passive measurements Netflow becoming mature

OC3MON hardware-based sampling of actual packets

Router support becoming available

Security

Security: An unusual Internet2 Emphasis

Aspects of Security Security of the infrastructure

Security of user host computers

Security of information and privacy

In the post-11-Sep environment Society will be less tolerant of lax standards

Not a distinctly 'Internet2' concern but one that all our universities share