Bandwidth management and qos

1. Bandwidth Management and
QoS
Shane Duffy
MEF Carrier Ethernet Certified
Professional

2. Basic history
• Circuit switched to Packet switched networks
• Circuit
– Dedicated circuit always provisioned from end to
end
• Packet Switched
– Allows better sharing and balancing of resources
while scaling.

4. Terminology I
• Bandwidth Management is the process of
controlling packets on a network link
– To avoid overfilling the link which would result in
network congestion
• Bandwidth Management may be referred to as:
– Bandwidth Control
– Bandwidth Throttling
– Rate limiting
– Token Bucket
– Leaky Bucket

5. Bandwidth [ limiting | shaping
|throttling ]
• Physical Ethernet standards
– 10Mb
– 100Mb
– 1000Mb | 1Gb
– 10000Mb | 10Gb
• How do we allocate a portion to users
– 5Mb | 30Mb

6. LAN to [ internet | WAN ]
Internet | WAN
Like a fire hose VS a garden hose

7. LAN to [ internet | WAN ]

8. QoS
• How do I make sure Business email gets
priority over Youtube.
• What services are impacted by network
performance

9. Terminology II
• QoS is a resource reservation system
– Its not a measure of achieved quality or a guarantee
of quality
– It’s a work around for congestion
– Its especially important with latency sensitive
applications
• QoS (Quality of Service) may be referred to as:
– DSCP (Differentiated services code point)
– ToS (Type of Service)
– IntServ (Integrated Services)

10. QoS

11. Questions
Next section can get really technical

12. Technical Session
• Leaky Bucket
• Token Bucket
• Multiple Buckets
• Egress & Ingress (Where to implement?)
• Carrier Ethernet
• QoS

13. Leaky Bucket
Packets are discarded when the bucket is full

14. Token Bucket
Looks almost the same? Lets discuss

15. Leaky VS Token Bucket
• LB discards packets; TB does not. TB discards
tokens.
• With TB, a packet can only be transmitted if
there are enough tokens to cover its length in
bytes.
• LB sends packets at an average rate. TB allows
for large bursts to be sent faster by speeding
up the output.
• TB allows saving up tokens (permissions) to
send large bursts. LB does not allow saving.

16. Multiple chained buckets

17. Carrier Ethernet
• A ubiquitous, standardized, carrier-class
Service and Network defined by five attributes
that distinguish it from familiar LAN based
Ethernet

18. Carrier Ethernet

19. Bandwidth profiles and traffic
management
Bandwidth Profiles per EVC & per Class of Service Governed by 6 Parameters
– CIR (Committed Information Rate)
• CIR defines assured bandwidth
• Assured via bandwidth reservation, traffic engineering
– EIR (Excess Information Rate)
• EIR bandwidth is considered ‘excess’
• EIR improves the network’s Goodput
• Traffic dropped at congestion points in the network
– CBS/EBS (Committed/Excess Burst Size in bytes)
• Higher burst size results in improved performance
Color Mode (“Color Aware” or “Color Blind”)
– When set as “Color Aware” governs discard eligibility
• Marking typically done at ingress
• Green – Forwarded frames – CIR conforming traffic
• Yellow – Discard Eligible frames – Over CIR , within EIR
• Red – Discarded frames – Exceeds EIR
Coupling Flag (set to 1 or 0) governs which frames are classed as yellow
EVC-1 EVC-2
EVC-3
EIR

20. CE Bandwidth Profiles
• Bandwidth Profiles can divide bandwidth per EVC over a single UNI
– Multiple services over same port (UNI)
– CoS markings enable the network to determine the network QoS to provide
UNI
EVC1
EVC2
EVC3
Ingress
Bandwidth Profile
Per Ingress UNI
Port-based
UNI
EVC1
EVC2
EVC3
Ingress Bandwidth
Profile Per EVC1
Ingress Bandwidth
Profile Per EVC2
Ingress Bandwidth
Profile Per EVC3
Port/VLAN-based
UNI EVC1
CE-VLAN CoS 6 Ingress Bandwidth Profile Per CoS ID 6
CE-VLAN CoS 4
CE-VLAN CoS 2
Ingress Bandwidth Profile Per CoS ID 4
Ingress Bandwidth Profile Per CoS ID 2
EVC2
Port/VLAN/CoS-based

21. Carrier Ethernet in Action
Application EVPL Profiles, Sample CoS ObjectivesCarrier Ethernet Service Provider
Committed
Information
RatePriority
Excess
Information
Rate
10 mbps0 0
100 mbps1 0
50 mbps2 0
40 mbps3 0
04 500 mbps
Metro Fiber Ethernet Virtual Private Line Services
VoIP calls
Interactive
business and consumer
video programming
Telepresence
Streamed HD
live content
Content distributed.
Development and
non-real time delivery
UNICOMPANY
HQ
Frame
Delay
5ms
5ms
25ms
N/A
N/A
Frame
Loss
Ratio
0.1%
0.01%
0.1%
0.01%
1%
Implementation Guidance
• The above bandwidth profiles and related Performance metrics are a small set of those available.
• New MEF Specifications recommend performance objectives based on both distance and application types
Impact for Providers and Enterprises
• Ability to tune Carrier Ethernet services to exactly match wide variety of changing applications requirements
creates a highly responsive network that reacts well to bursts of high priority data.