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Bay Area Network Virtualization In this Tech Talk, Harry will address two questions: What are the differences between LANs and the WANs that impact network virtualization? Why should Virtual Networkers care about the hardware? When Apr 23rd 2014 RSVP @ http://www.meetup.com/openvswitch/
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Ultimately All Clouds Are
Made of [email protected]
4/23/2014HV Quackenboss 2014 All Rights Reserved [email protected] 1
Why the Title?
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Dave Roberts Tweet
“But all clouds are
ultimately made of
metal.”
Dave Roberts
Senior Vice President, ServiceMesh
Tweet, August 2, 2012
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Most Everybody Thinks SDN
Is the Solution
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SDN
Mobile NetworkDatacenter
Opinion (I)
The more you understand the metal,
the more you will understand SDN, NFV
and Network Virtualization
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Opinion (2)
WAN SDN ≠ LAN SDN
WAN Virtualization ≠ LAN Virtualization
Differences come from:
Physics
Economics4/23/2014HV Quackenboss 2014 All Rights Reserved [email protected] 6
Opinion (3)
Mobile WAN ≠ Wired WAN
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Physics & Econ Differences
WAN LAN
LATENCY ∞ 0
BANDWIDTH 0 ∞
COST ∞ 04/23/2014HV Quackenboss 2014 All Rights Reserved [email protected] 8
Do the same SDN
solutions apply?
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Campus Wi-Fi
Datacenter
LAN
Mobile
Networks
Broadband and
Long haul Networks
WAN Providers’ Challenge“A common refrain among the network executives we’ve talked to is that, if IT services can be provided in secondswith cloud computing technologies, it should not take days or weeks to deliver the network services that support them.”
Practical Implementation of SDN & NFV in the WAN
Heavy Reading
October 2013
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London Mobile Infrastructure
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600 Base Stations
See the Cell Tower?
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Mobile Operators’ Finance Problem
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3G Mobile Network Metal
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Big device population
Complex
Heterogeneous
10 year depreciation
3G May Be the Future of IoT
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Mobile SDN/NFV Perspective
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Been “SDN” since before SDN
Salivating over IoT
NFV Mandatory Requirements
Existing OSS/BSS integration
Existing equipment interoperability
• Including legacy 3G
“Wired” WAN
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Sprint Long Haul Network
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Latency and Light Speed300,000 km/sec (in vacuum)
~200,000 km/sec (in fiber)
Slower because of refraction
Ask your neighborhood physicist
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http://en.wikipedia.org/wiki/Optical_fiber
Cross-Country Latency
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Source: Comcast
(4,100/200,000) =~.020 seconds
Packets go through routers, which buffer
adding delay
WAN Latency Is Speed-Independent
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Source: Comcast.com 40G/sec network
BANDWIDTH LATENCY
40Gbps 20 milliseconds
400Gbps 20 milliseconds
1Mbps 20 milliseconds
Ping (Half Moon Bay to Palo Alto)
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Half Moon Bay to New York
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Half Moon Bay to Beijing
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Half Moon Bay to New Delhi
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Latency Vs. BandwidthThought experiment:
Transfer 1 Petabyte of data on 1TB SATA drives from SFO to New Delhi• Note: SATA III throughput: 6 Gbits/sec
• SATA drive: ~100 Mbytes/sec (~1.1Gbps)
Alternatives
A. Lease dedicated 40G circuit
B. Airplane 1000 drives (~2000 lbs)
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Latency Vs. BandwidthA: 40G pipe
1-way latency: ~100ms (best case)
• (first bit in to first bit out)
~70 hours
• Hypothetical ideal throughput
Option B: Airplane
~18 hours (assuming non-stop)
1-way latency: ~18 hours
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WAN Cable CostsResidential broadband installation
CAPEX: ~$1,000/home passed
OPEX: ~$5/month/homehttp://fastnetnews.com/fiber-news/175-d/4835-fiber-economics-quick-and-dirtynth
Long distance fiber installation
$30K/mile for conduit in open
trench during road construction
(< 1% of cost of road)
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Transportation Industry LessonsUtilization is key to low cost
Synchronize
Schedule in advance
Take time to pack (doesn’t hurt overall time much)
Load big stuff first
Make sure there is a full buffer at on ramp
Make sure there isn’t a bottleneck unloading
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Datacenter LANs
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Samsung Backup
Datacenter Fire
April 20,2014
Mice + Elephants
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Source: Facebook OIC 2013 presentation
East-West Traffic Example
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Source: Facebook OIC 2013 presentation
Typical Cloud Data Center20 to 30 1U(1.75”) servers/rack
2x1U Top of Rack switches
Switches are 5% to 15% of rack
space, CAPEX and electricity
BUT: about 3 switch ports per server
(15% to 45% of server CAPEX)
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Datacenter Topology
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(HVQ Note: For each TOR Switch server port, there will be ~1 to 2
aggregation ports)
Source: Nathan Farrington Facebook OIC13 Presentation
TOR (Top of Rack) Switch48x10GE + 4x40GE
Vol. price (est.)
~$2500-$4000
Per port $50+
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Source: Opencomute.org Intel draft
spec
Example OCP
Bare Metal Switch
Cabling Cost > TOR CostCopper Twinax: ~$75/link
Intra-rack (server to TOR)
Fiber optics: ~$150 - $400
(2Xoptics + cable)
Rack to spine switch
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Aggregation CablingMTP/MPO multifibre cables
12,24…up to72 fibers
Intel/Corning Silicon Photonics (future)
Up to 64 fibers - 25Gbps each
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http://www.intel.com/content/www/us/en/research/intel-labs-silicon-photonics-mxc-connector.html
Data Center Metal Economics
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Datacenter Metal Key PointsServer networking switches CAPEX is
20% to 30% of server cost
TOR switch hardware is pretty much same for everybody
Weakening perception that brand name SW is better is reducing margins
In-rack connectivity with copper cables is cheap, but still as much or more than the switch $/port
Limited opportunities to reduce hardware CAPEX
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Bandwidth Vs CPU1 instruction needs 1 byte of
memory and generates 1 bit/sec of bandwidth
(1994) SPARC10: 60Mhz+100Mbps
(2000) 1Ghz CPU+1GbE
(2014) (3Ghz*15 cores) * 2 sockets
90Gbps (!)
Do datacenters have
enough NIC bandwidth?
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Performance in Datacenter LANs
Latency and Bandwidth
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Server Latency (One Way)
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TCP/IP
Stack
GBE NIC
Server With GbE
~15µsTCP/IP
Stack
10GE NIC
Server With GbE
~5µs
Note: numbers may vary based
on specific benchmarks
Switch Latency Is Less Than
Host Stack Latency
First bit in to first bit out
Measurement favors “cut-through” (versus “store and forward” switches
Typical 10GE (per-chip) .3µs to 1.5µs
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IP
PHY
Data Link Data Link
PHY
Switch Latency With Buffering
Switch buffers if output port busy
Dramatic increase in latency
60µs observed in benchmark tests
Dropped packets/retransmits: ∞ latency
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IP
PHY
Data Link Data Link
PHY
BUFFER
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Source: HP Mellanox Low Latency Benchmark Report 2012
Round-trip user space to
user space
Who Cares About LAN Latency?Not if traversing the WAN
But high latency and dropped hurt
server throughput
Applications spin or get swapped
out
HFT cares!
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HFT: Milliseconds = $$$ While You Were Blinking
High-frequency-trading activity is not constant; it occurs in microbursts. The line at the bottom of this graphic is the stock-market activity involving General Electric shares over 100 milliseconds (one-tenth of a second) at 12:44 p.m. on Dec. 19, 2013. The gray box magnifies a five-millisecond window, during which GE experienced heavy bid and offer activity and a total of 44 trades.
Graphic: CLEVERºFRANKE.
Data source: IEX.
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44 trades in 5 milliseconds
http://www.nytimes.com/2014/04/06/magazine/flash-boys-michael-lewis.html?_r=0
Leveling the HFT Playing FieldTo allow customers to
pick and choose
different pricing tiers
based on different
latencies, HFT systems
add latency using fiber
38 miles of fiber cable =
~260 microseconds
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http://www.nytimes.com/2014/04/06/magazine/flash-boys-michael-lewis.html?_r=0
Latency Key PointsFrom viewpoint of end-end across WAN, LAN
latency is near 0
10GE Host NIC and IP Stacks have improved dramatically
1GE is > 10X higher than 10GE
Few 1GE switches support cut through
Higher chance of busy ports
Switch latency in cut through is great
If switches have to buffer because of busy output port, latency goes way up
Latency spikes are short duration so hard to see, let alone measure
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OpenFlow For Datacenter LANs
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Note: The control plane
network switches are
not shown in this
diagram
OpenFlow Reaction Time in LAN
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OpenFlow
Application
Transport Layer
Internetwork Layer
NIC
OpenFlow
Agent
Transport Layer
Internetwork Layer
NIC
1000µs
30µs
20-100µs
30µs
1000µs
OpenFlow Controller
App + IP Stack
OpenFlow Switch
Agent + IP Stack
OpenFlow MicroControllers?
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http://www.theregister.co.uk/2012/12/11/pica8_sdn_bundles/
OpenFlow
MicroControllerOpenFlow
MicroController
Master
OpenFlow
Controller
Lessons From Transportation
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Multi-pathingHOV lanes
Priority based on
policy
Inefficient utilization
What if nobody
changed lanes?
(802.11ag and ECMP
are static)
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Dynamic Load Balancing Can Increase
Throughput
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“It's tough to make predictions, especially about the future.”
― Yogi Berra
http://www.pcper.com/news/General-Tech/Atom-aint-dead-yet-New-ultra-low-power-Avoton-chips-servers
Lower Performance =
Higher Efficiency
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New Rack DesignsSince the 1U server was invented by
Cobalt Networks (acquired by Sun)
the processors are > 100X faster
Network switching has
(mostly)lagged Moore’s Law
Will ratio of servers to network
switches decreases over time?
Time for new form factors?
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TOR Switch Obselescence
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Source: Intel IDF 14 Shenzhen presentation
Data Center Server Future
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Source: Intel IDF 14 Shenzhen presentation
TOR Switch Evolves to Tray Switch
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Source: Intel IDF 14 Shenzhen presentation
Conclusions
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WAN Issues and OpportunitiesMobile: physical infrastructure
complexity has led to management
complexity
NFV promise is to reducing
physical devices, simplify mgt.
Long haul: utilization of capacity is
still opportunity, SDN offers ways to
simplify mgt. and improve utilization
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Datacenter LANsLow cost of switching has limited
opportunities for independent SDN controller sales
Distributed SDN MicroController hierarchy should broaden appeal
Controller needs to be bundled with switch or switch software
Effective dynamic load balancing will improve throughput and latency
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Important DifferencesWAN LAN
COST ∞ 0
BANDWIDTH 0 ∞LATENCY ∞ 0
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Ultimately All Clouds Are
Made of [email protected]
4/23/2014HV Quackenboss 2014 All Rights Reserved [email protected] 66