Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research...
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![Page 1: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/1.jpg)
Using Measurement Data to Construct a Network-Wide
View
Jennifer RexfordAT&T Labs—Research
Florham Park, NJ
http://www.research.att.com/~jrex
![Page 2: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/2.jpg)
Motivating Applications
• Basic usage reporting and trending– Application mix (P2P, Web, DNS, etc.)– Characterization per customer, per peer, etc.
• Network troubleshooting– Detect, diagnose, and fix problems in real time– Traffic: flash crowds, DDoS attacks, new hot apps– Routing: route flaps, blackholes, highjacked prefixes
• Traffic engineering and capacity planning– Tuning routing configuration to the prevailing traffic– Deciding where to add new links, new peers, etc.– Predicting the effects of the changes in advance
Need: network-wide view of topology, traffic, and routing
![Page 3: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/3.jpg)
Measure, Model, and Control
Topology/configuratio
n
Changes tothe network
Operational network
Network-wide“what if”
tools
measure control
Offeredtraffic
Routeupdates
model
![Page 4: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/4.jpg)
Network-Wide View
• Topology and configuration– Up routers, links, and routing sessions– Current IGP weights and BGP policies
• Offered traffic– Load between ingress and egress points– Traffic per destination prefix per ingress– Slice and dice by IP prefixes, port #s, etc.
• Routing advertisements– Routes learned via each eBGP session– All routes, before any import processing
Need: ubiquitous support for traffic and route monitoring
![Page 5: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/5.jpg)
Traffic: Packet Sampling
• IETF working group on packet sampling (psamp)– http://www.ietf.org/html.charters/psamp-charter.html– Minimal functionality for packet-level measurement– Suitable for implementation in high-speed line cards– Tunable trade-offs between overhead and accuracy
• Basic idea: parallel filter/sample banks– Filter on header fields (src/dest, port #s, protocol)– 1-out-of-N sampling (random, periodic, or hash-
based)– Extract key header fields, output link, IP prefix, etc.– Send bundled group of records to a collection system
filter sample extract exportpacket record
![Page 6: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/6.jpg)
Routing: BGP and IGP Monitoring
• Limitations of today’s approaches– Periodic table dumps
• Pro: all of the routes (best and alternate)• Con: coarse timescale and high router overhead
– BGP session with operational router(s)• Pro: continuous feed and limited overhead• Con: only the best routes, after import processing
• Onboard support for route monitoring– Special monitoring session with the router– Continuous export of received routing
messages– Different data format for higher efficiency– Omission of redundant info (e.g., refresh LSAs)
![Page 7: Using Measurement Data to Construct a Network-Wide View Jennifer Rexford AT&T Labs—Research Florham Park, NJ jrex.](https://reader036.fdocuments.in/reader036/viewer/2022083008/56649ea45503460f94ba9115/html5/thumbnails/7.jpg)
Conclusion
• Control requires a network-wide view– Topology, traffic, and routing
• Ubiquitous views require vendor support– Traffic statistics and routing data
• Onboard support must be very lightweight– Operation on high-speed links and routers
• Traffic measurement with packet sampling– Parallel filter/sample/extract/export banks
• Routing data via special monitoring session– Relaying of received routing updates/LSAs