Transcript ppt 0.5MB - Star Tap

Advances Toward
Economic and Efficient
Terabit LANs and WANs
Lawrence G. Roberts
CEO Anagran
[email protected]
September 2005
Switching History – Byte, Packet, Flow
Switching Technology Improvement
Less Decisions / bit reduces routing cost, not port cost
Cost
1
TDM – One Byte per Decision
1 Byte
Decisions per Bit
0.1
$
1969
40:1
First Generation
0.01
ATM – 1 cell / decision
40 Bytes
52 Bytes
0.001
500 Bytes
0.0001
2003 14:1
Second Generation
0.00001
1960
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7000 Bytes
1970
1980
1990
2000
2010
What is a Flow Router ?
Packets
Flows
A Flow is a stream of packets between one user/system and another
– In IPv4 it is uniquely identified by the 5-tupple
• (Destination. Address, Source Address, Protocol, Destination Port, Source Port)
– In IPv6 it is uniquely identified by the 3-tupple
(
• D-Address. S -Address, Flow Label)
A Flow Router :
– Identifies the Flow in a Flow State Memory
– Routes the Flow if it is a new flow and determines the QoS (Rate, Delay, etc)
• QoS can be determined with ACL commands from DiffServ, Ports, Protocol, etc.
• QoS can also be signaled in the first packet using TIA 1039 or the ITU equivalent
– Subsequent packets in the flow are QoS controlled and switched to the output port
The result is less expensive, supports ATM quality QoS, and gains many
advantages from knowledge of the flow
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Bad
Comparison of Router Designs
Level 2 Packet
Level 2/3 Packet
Level 3 Packet
Broadcast Storms
MAC Routing
Best Route Only
Limited Routing
Best Route Only
High Cost
Best Route Only
Good
Address Total Net
Denial of Service
ACL Commands
DiffServ Priority
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Level 3 Flow Aware
Address Total Net
Denial of Service
ACL Commands
DiffServ Priority
Delay Control
Rate Control
Burst Tolerance
Precedence
Multiple Routes
DDOS Control
High Utilization
Fairness – P2P
Low Cost
Source Checking
Benefits of Flow Router Technology Supporting a Grid Center
Connect up over 1000 Servers together - 1 FSA Router
Higher Server Throughput ( 2:1 typical )
Layer 3 Routing - no broadcast noise, Secure Subnets
QoS for Video, Voice, and Storage Transfers
Disaster Recovery can use Guaranteed Rate
Multiple Routes Available for any Path
Backup
Site
10 GE
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Network
GE
Benefits at the Edge of a WAN
Guaranteed Rate IP and/or MPLS Tunnels Used
to interconnect Flow Routers and provide
Guaranteed Rate sub-network
DSL
Video Server
Node Used for
Switching
Could use
multiple nodes
DSLAM’s
Control QoS at the Edge
Provide Fairness
Support Video and Voice
Route over best path
Packet Router
FSA Router
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Ethernet to Buildings
WiFi Mesh
Current Core Network
CMTS
• Route Premium Traffic over Red
• Guarantee Voice/Video end-to-end
• Route Best Effort over Blue
• Use all current capacity
Cable Networks
QoS Signaling (TIA 1039 and ITU) Allows TCP Jumpstart
TCP Tim e to Get 1MB Page
AR=100
AR=30
Sender
Cr os s Countr y - RTT=100 m s
IPv6 r ate ne gotiate d of 32 M bps
Receiver
AR=30
1,200
TCP Today
IPv4
W ith QoS Signaling
and
1,000 32 M bps agreed
AR=30
With QoS W ith TCP Slow -Start
IPv6/QoS
Signaling
32 M bps TCP
Rate Negotiated
800
K i lo B ytes
• Available Rate is requested and negotiated
down across the network, returning the best
rate available
• The Sender can then Jump TCP to that rate
• If the network changes, a new rate is returned
• If errors occur, the user need not reduce rate
Typical TCP Slow Start
600
400
200
0
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Se conds
Major Improvement in Page Access over Long Delay (Satellite) or
High Error rate (Radio) paths
10:1 Faster for Cross Country
20:1 Faster for Satellite or Noisy Radio
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Flow Routers Support Guaranteed Rate Flows
New Flow Discarded since over limit
New Flow Accepted since under limit
GR Limit
Link
Capacity
New High Priority Flow Accepted
When precedence is enabled, new flow of high
priority if over capacity is accepted and lower
priority flow is dropped
Low Priority Flow Dropped
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• Without QoS signaling, GR flows are rejected
when max capacity is reached
• With QoS Signaling (TIA 1039 or ITU) the flow has
a precedence which is used to determine which flows
are rejected
• Precedence is critical for emergency services and
military, important for office and home
GR=2
GR=2
Sender
Receiver
QoS Signaling for Guaranteed Rate
Summary
For 35 years it has been believed that keeping flow information or
“State” is bad-all IP routers were developed without using flow state
Now, economics have changed and flow state or FSA can:
– Significant Cost Reduction from Standard Layer 3 IP Packet Router
• Flow Memory cost too much to do Flow Routing for first 20 years
• Now Packet Routing costs too much and routing once per flow is less expensive
–
–
–
–
–
–
–
Raise Utilization to 83% from 40% due to major reduction in Variance
Control QoS for Guaranteed SLA’s (Video, Voice, Gaming)
Allow Load Balancing across all near-equal-cost paths in network
Improve Security with DDOS protection and Flow Authorization
Provide Fairness and Accounting
Permit QoS to be signaled and agreed on end-to-end across a network
GR IP Tunnels allow total scalability of VPN’s with signaled setup
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