technology and administrative coordination issues pacific rim networking workshop guy almes manoa...
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Technology and Administrative Coordination Issues
Pacific Rim Networking WorkshopGuy Almes <[email protected]>
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