towards an evolvable internet architecture
DESCRIPTION
change IP (routers, headers, addressing, …). Towards an Evolvable Internet Architecture. IP layer. Sylvia Ratnasamy (Intel Research), Scott Shenker (U.C. Berkeley/ICSI), Steven McCanne (Riverbed Tech.). hh Folklore ff. The Internet Architecture needs fixing - PowerPoint PPT PresentationTRANSCRIPT
Towards an Evolvable Internet Architecture
IP layer
change IP (routers, headers, addressing, …)
Sylvia Ratnasamy (Intel Research), Scott Shenker (U.C. Berkeley/ICSI), Steven McCanne (Riverbed Tech.)
Folklore
• The Internet Architecture needs fixing– IPNL, Triad, IP Multicast, Pushback, GIA, Traceback,
IPv6, SIFF, FQ, CSFQ, XCP, Capabilities, DTN, HLP,
RCP, AIF, i3, LFN, …
• But, ISPs don’t deploy (our) fixes– IP Multicast, IPv6 are the success stories!
• One reaction: ``Who needs the ISPs
anyway?’’
Overlays to the Rescue (v1)
Use overlays to augment IP• Implement change in application-level
`routers’– Multicast: ESM (CMU), commercial CDNs
– Routing: InterNAP, RON (MIT), SOSR (UW)– Quality-of-Service: OverQoS (UCB/MIT)– DoS: Mayday (MIT), SOS (Columbia), i3 (UCB/CMU)
Overlays to the Rescue (v1)
Use overlays to augment IP• Implement change in application-level
`routers’• Practical
– bypass CISCO and the ISPs
Overlays to the Rescue (v1)
Use overlays to augment IP• Implement change in application-level
`routers’• Practical• Often even appropriate
– keep complexity out of IP
Overlays to the Rescue (v1)
Use overlays to augment IP• Implement change in application-level
`routers’• Practical• Often even appropriate
But, if the problem is best solved at the IP layer, this doesn’t help
Overlays (v2)
Use overlays to undermine ISPs [Peterson, Shenker, Turner 04]
• Next-Generation Service Provider (NGSP) enters the market
– overlays a new architecture atop existing ISPs– legacy ISPs soon serve only to access NGSP
Overlays (v2)
Use overlays to undermine ISPs [Peterson, Shenker, Turner 04]
• Next-Generation Service Provider (NGSP) enters the market
• Eventually, NGSP replaces ISPs– lease dedicated lines
Overlays (v2)
Use overlays to undermine ISPs [Peterson, Shenker, Turner 04]
• Next-Generation Service Provider (NGSP) enters the market
• Eventually, NGSP replaces ISPs
• Technically, practical and broad– (and invaluable as an experimental platform)
Overlays (v2)
Use overlays to undermine ISPs [Peterson, Shenker, Turner 04]
• Next-Generation Service Provider (NGSP) enters the market
• Eventually, NGSP replaces ISPs
• Technically, practical and broad
But, requires disrupting the existing market structure
• Evolution through (repeated) revolution
Are there other (more conservative) options?
This Paper
• Can we enable evolution that – can retain the existing market structure– yet, allows non-incremental change(revolution through evolution )
• Approach: – design for evolution (vs. causing
evolution)
Design for Evolution
The Internet will always be – multi-provider– decentralized in control
Common complaint– providers have little incentive to innovate
Is this due to flaw(s) in the architecture?– strategies, mechanisms, hooks that assist
evolution
Disclaimer
Many possible reasons for ISP reluctance– architectural barriers to innovation– economic barriers (pricing models, etc.)– disconnect between research and reality
• maybe the Internet is doing just fine• maybe the fixes we propose aren’t the right
ones
This paper: architectural barriers– may well be the least of the problems
Outline
• Toy example: deploying IPvN• Universal Access• Implementing Universal Access• Conclusion
Paper
When a new version of IP, call it IPvN, is defined, what conditions would lead ISPs to deploy it?
Toy Example
IPvN supports comprehensive security– requires router support – new IP headers
• Software vendor puts out an IPvN stack
• Router vendors support IPvN
• Content Provider (CP) is interested in using IPvN
• ISPs consider deploying IPvN Servers
Deploying IPvN
IPv4ISP A
CP
Servers
scale partial deployment a necessitypartial deployment partial usability
partial deployment partial usability
partial usability global usability
development of applications/services
stalled on global usability
low usage, user demand
no incentive for ISPs to deploy IPvN
any ISP can gate usability
global deployment
independent innovation is high risk, yet offers no competitive advantage
• require global usability under partial deployment
Proposal: separate deployment from usability
partial deployment global usability
IPv4ISP A
X
Servers
Universal Access
If even a single ISP deploys IPvN, any endhost can use IPvN
– enables customer choice, demand– encourages application development– no ISP can gate adoption– independent innovation; others follow to compete
Note assumption: UA leads to increased revenue flow– settlements?– application/service providers
Outline
• Toy Example: deploying IPvN• Universal Access• Implementing Universal Access
– constraints– two components– putting it all together
• Conclusion
Achieving UA
Constraints:– partial deployment
– partial ISP participation
– allow participating ISPs control
– existing players– existing contractual agreements
Achieving UA: Two components
IPv4ISP A
(1) partial deployment multi-provider overlays*
Achieving UA: Two components
IPv4ISP A
(2) universal access need redirection
Redirection for UA
Involves knowing:
– where IPvN routers are located
– which IPvN router is the best choice for a source
(And the answer to both changes as deployment spreads!)
Mechanism is ~tunneling++
Key is who effects redirection
Redirection: Options
Who Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Redirection: Options
Who
• user: unwieldy
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Redirection: Options
Who
• user: unwieldy
• user’s ISP
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Redirection: Options
Who
• user: unwieldy
• user’s ISP
• participant ISPs
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Redirection: Options
Who
• user: unwieldy
• user’s ISP
• participant ISPs
• application-layer
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Redirection: Options
Who
• user: unwieldy
• user’s ISP
• participant ISPs
• application-layer
• network-layer
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
Network-Layer Redirection
Routers perform redirection
Network-Layer Redirection
Routers perform redirection
Challenge: no explicit participation from ‘ ’
Proposal: Use IP Anycast
1. ‘A’ is the IPv(N-1) address used to deploy IPvN
2. IPvN routers advertise ‘A’ into the IPv(N-1) routing protocol
3. a discovers IPvN routers via IPv(N-1) routing protocol
A AA
AAA
IPv4 DST = A
Redirection: Options
Who
• user: unwieldy
• user’s ISP
• participant ISPs
• application-layer
• network-layer*
Recall Constraints
1. partial deployment
2. partial ISP
participation
3. participant ISP
control
4. no new players
5. existing contracts
*Caveat: less flexible redirection
But, Isn’t Anycast a Non-Starter?
Short answer: no.
• Scales just fine– restricted service model vis-à-vis RFC 1546
• deployed/used only by ISPs– a new IP needs one anycast address
• And is deployable (see paper)– Intra-domain: minor change by participating ISPs– (+) Inter-domain v1 : simple policy change by all ISPs– (~) Inter-domain v2: no change by non-participant
ISPs
Outline
• Toy Example: deploying IPvN• Universal Access• Implementing Universal Access
– constraints– two pieces– putting it all together
• Conclusion
Putting It All Together
A AA
IPv4 DST = A
Dn
source
IPvN DST =Dn
A A
Case 1: Destination’s ISP supports IPvN
IPv4 DST = R
IPvN DST =Dn
R
A AA
IPv4 DST = A
?
source
IPvN DST = ?
A
Two issues:
1. Addressing hosts in non-participant ISP domains
Case 2: Destination’s ISP does not supports IPvN
A AA
IPv4 DST = A
D4-to-n from D4
source
IPvN DST = D4-to-n
A
Two issues:
1. Addressing hosts in non-participant ISP domains
• proposal: interim addressing à la RFC 3056
Case 2: Destination’s ISP does not supports IPvN
A AA
D4-to-n from D4
sourceA
Two issues:
1. Addressing hosts in non-participant ISP domains
2. Routing to hosts in non-participant ISP domains (paper)
• one proposal: advertises D4’s prefix into IPvN routing
Case 2: Destination’s ISP does not supports IPvN
D4-to-n ?
R
R
A AA
D4-to-n = from D4
sourceA
Two issues:
1. Addressing hosts in non-participant ISP domains
2. Routing to hosts in non-participant ISP domains (paper)
Case 2: Destination’s ISP does not supports IPvN
IPv4 DST = D4
Putting It All Together
Summary: Technical requirements for UA
1. Redirection– best achieved at the network-level – anycast: works under partial participation
2. Multi-provider virtual backbones– similar to the MBone, etc.– but, details of addressing and routing to
destinations in non-IPvN domains requires some attention
Open Questions
• End-host software architecture– dual-stack, NAT-PT, BIS, OCALA [UCB]
• Exploring revenue flow: – ongoing work at SIMS (UCB) [Laskowski, Chuang]
• Architectural limitations due to partial deployment, overlays
• Clean-slate design for evolvability
Conclusion
Proposal: A conservative approach to evolution [Floyd]– a preference for incremental strategies (that lead
in the fundamentally right direction?) – value to understanding the compromises possible
with existing network vs. brave new solutions
Conclusion
Proposal: A conservative approach to evolution [Floyd]
Conjecture: UA could enable ISP innovation– achievable with no change to the current
architecture– a bit of synthesis, but no new mechanisms
Conclusion
Proposal: A conservative approach to evolution [Floyd]
Conjecture: UA could enable ISP innovation
Maybe the Internet is evolvable
Maybe the problem is not a technical one– worth exploring to avoid repeating the same
mistake
Or, maybe there is no problem
Thank you!