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© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 1
Características y evolución de las redes LAN y WAN para ofrecer servicios de Comunicación Unificada
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 2
Buenos Días a todos…!
Systems EngineerPublic Sector
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 3
MediaResources
UC Processing
AgentsGateway/
SurvivableRemote
PSTN/IPGateway
UCEndpoints
CommsEndpoints
PSTN
UC Infrastructure
Network InfrastructureWAN
AggregationRouter
BranchRouter
Distribution/
Core SwitchCampus
Branch
IP WAN
AccessSwitch
AccessSwitch
The Elements of Unified Communications
SiSi
Conf
Xcode
SiSi
MTP
ApplicationsVoice Mail/
Unified Messaging
Web /Audio/Video
Conferencing
XML Phone
Services
LDAPDirectory
GK
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 4
Network Infrastructure Agenda
Building a Campus Network
QoS in the Campus
QoS in the WAN
Qos in the Wireless LANs
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 5
Systems Architecture
Bay Bridge:
Original cost in 1936: $1.1 billion (adjusted for today’s $)
Estimated cost to expand: $6.2 billion… and climbing
Golden Gate Bridge:
Original cost to in 1937: $446 million (adjusted for today’s $)
A Poorly Planned Architecture A Well Planned Architecture
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 6
SiSi SiSi
SiSiSiSi
SiSi SiSi
Building a Campus Network Hierarchical Network Design
Building Block
Without a Rock Solid Foundation the Rest Doesn’t Matter
Access
Distribution
Core
Distribution
Access• Offers hierarchy – each layer has specific
role
• Modular topology - building blocks
• Easy to grow, understand, and troubleshoot
• Creates small fault domains – Clear demarcations and isolation
• Promotes load balancing and redundancy
• Promotes deterministic traffic patterns
• Incorporates balance of both Layer 2 and Layer 3 technology, leveraging the strength of both
• Utilizes Layer 3 Routing for load balancing, fast convergence, scalability, and control
• Sub second convergence possible
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 7
Building a Campus Network—The Access Layer
Aggregates network end-points
Layer 2/Layer 3 feature rich environment; convergence, HA, security, QoS, IP multicast, etc
Intelligent network services: QoS, trust boundary, broadcast suppression, IGMP snooping
Intelligent network services: Rapid PVST+, EIGRP, OSPF, DTP, PAgP, UDLD, etc.
Catalyst® integrated security features 802.1x, Port security, DHCP snooping, Dynamic ARP Insp, IP Source Guard, etc.
Automatic phone discovery, conditional trust boundary, Power Over Ethernet, auxiliary VLAN, etc.
Spanning tree toolkit: Portfast, UplinkFast, BackboneFast, LoopGuard, BPDUGuard, BPDUFilter, RootGuard, etc.
To Core
SiSi SiSi
VLANS do not span access switches
Feature Rich Environment—Not Just About Connectivity
Access
Distribution
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 8
Campus Network—Access Layer
During initial CDP exchange phone is configured with a Voice VLAN ID (VVID)
Phone also supplied with QoS configuration via CDP TLV fields
Quality—Separation of broadcast domains i.e. phones and PCs are on separate subnets
Security—Different network policies for different subnets; WORM attacks can be contained to the PC VLANs.
PC VLAN = 10
(PVID)
Phone VLAN = 110
(VVID)
802.1Q encapsulation with 802.1p Layer 2
CoS
Voice and Data VLANs
Native VLAN (PVID) No Configuration Changes
Needed on PC
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 9
Building a Campus Network—The Distribution Layer
Availability, load balancing, QoS and provisioning are the important considerations at this layer
Aggregates wiring closets (access layer) and uplinks to core
Use Layer 3 switching in the distribution layer
Protects core from high density peering and problems in access layer
EIGRP/ OSPF - Route summarization, passive interfaces to access layer, sub second convergence possible with timer adjustment, redundant path load sharing
HSRP or GLBP to provide first hop redundancy, sub second convergence possible with timer adjustment
Spanning tree features ( Only if needed ):
Setting STP Root, Root Guard, Rapid PVST+—Per VLAN 802.1w
SiSiSiSi SiSi SiSi
Access
Distribution
Policy, Convergence, QoS, and High Availability
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 10
Building a Campus Network—The Core Layer
Backbone for the network—connects network building blocks
Performance and stability vs. complexity—less is more in the core
Aggregation point for distribution layer
Tune routing protocol timers for sub second convergence
Separate core layer helps in scalability during future growth
Use hardware accelerated services only to maintain performance
Access
Distribution
Core
Scalability, High Availability, and Fast Convergence
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 11
Campus Design Best PracticesFirst Hop Redundancy
Used to provide a resilient default gateway/first hop address to end stations
HSRP, VRRP, and GLBP alternatives
VRRP, HSRP and GLBPprovide millisecond timersand excellent sub second convergence performance
VRRP if you need multi-vendor interoperability
GLBP facilitates uplink load balancing
Preempt timers need tobe tuned to avoid black-holed traffic
Data CenterWAN Internet
Layer 3 Equal
Cost Link’sLayer 3 Equal
Cost Link’s
SiSi SiSi SiSi SiSi SiSi SiSi
SiSiSiSi
SiSiSiSi
SiSi SiSiSiSiSiSi
1st Hop Redundancy
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 12
Campus Design—Routed Access Layer
Tune CEF load balancing
Match CatOS/IOS Ether-channel settings and tune load balancing
Summarize routes towards core
Filter routes towards the access
Disable Ether-channel unless needed
―Set port host‖ on access layer ports:
Disable Trunking
Disable Etherchannel
Enable PortFast
RootGuard or BPDU-Guard
Use security features
VLAN 120 Voice10.1.120.0/24
P-t-P Link
Layer 3
VLAN 20 Data10.1.20.0/24
VLAN 140 Voice10.1.140.0/24
VLAN 40 Data10.1.40.0/24
SiSi SiSi
SiSi SiSi
Access
Distribution
Core
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 13
Building a Campus NetworkSummary
Access layer
Rapid Per-VLAN spanning-tree ( PSVT +)
Rootguard
Portfast
UplinkFast
Layer 3 to the edge ?
Distribution Layer
HSRP/GLBP with load balancing
OSPF/EIGRP configured for fast convergence
Core Layer
OSPF/EIGRP configured for fast convergence WAN Internet PSTN
Server Farm
DistributionLayer 3
CoreLayer 3
AccessLayer 2
DistributionLayer 3
AccessLayer 2
http://www.cisco.com/en/US/netsol/ns656/networking_solutions_design_guidances_list.html#anchor2
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 14
Network Infrastructure Agenda
Building a Campus Network
QoS in the Campus
QoS in the WAN
QoS in the Wireless LANs
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 15
Enabling QoS in the CampusTraffic Profiles and Requirements
Latency ≤ 150 ms
Jitter ≤ 30 ms
Loss ≤ 1%
One-Way Requirements
Smooth
Benign
Drop sensitive
Delay sensitive
UDP priority
Voice
Bandwidth per CallDepends on Codec,Sampling-Rate, and Layer 2 Media
Bursty
Greedy
Drop sensitive
Delay sensitive
UDP priority
Video-Conf
Latency ≤ 150 ms
Jitter ≤ 30 ms
Loss ≤ 1%
One-Way Requirements
IP/VC has the SameRequirements as VoIP, but Has Radically Different Traffic Patterns (BW Varies Greatly)
Smooth/bursty
Benign/greedy
Drop insensitive
Delay insensitive
TCP retransmits
Data
Data Classes:
Mission-Critical Apps
Transactional/Interactive Apps
Bulk Data Apps
Best Effort Apps (Default)
Traffic patterns for Data Vary Among Applications
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 16
Why QoS in the Campus Protect the Good and Punish the Bad
QoS does more than just protect Voice and Video
For "best-effort" traffic an implied "good faith" commitment that there are at least some network resources available is assumed
Need to identify and potentially punish out of profile traffic (potential worms, DDOS, etc.)
Scavenger class is an Internet-2 Draft Specification => CS1/CoS1
Access Distribution Core
Voice Voice
Data Data
Scavenger Scavenger
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 17
Type Data FCSPTTAG
4 Bytes
802.1Q/pHeader
PRI VLAN IDCFI
Enabling QoS in the Campus Layer 2 Classification: 802.1p, CoS
802.1p user priority field also called Class of Service (CoS)
Different types of traffic are assigned different CoS values
CoS six and seven are reserved for network use
Three Bits Used for CoS(802.1p User Priority)
SADASFDPream.
Ethernet Frame
1
2
3
4
5
6
7
0 Best Effort Data
Medium Priority Data
High Priority Data
Call Signaling
Video Conferencing*
Voice Bearer
Reserved
Reserved
CoS Application
* Including Audio and Video
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 18
Enabling QoS in the Campus Layer 3 Classification: IP Precedence, DSCP
IPv4: three most significant bits of ToS byte are called IP precedence—other bits unused by IP precedence
DiffServ: six most significant bits of ToS byte are called Diff Serv Code Point (DSCP)—remaining two bits used for flow control
DSCP is backward-compatible with IP precedence
DSCP values correspond to Per Hop Behavior (PHB) designations
RFC 2474 provides more information on DSCP; also, see appendix in this presentation
IPv4 Packet
Standard IPv4
DiffServ Extensions
7 6 5 4 3 2 1 0
ID Offset TTL Proto FCS IP SA IP DA DataLenVersionLength
ToSByte
DiffServ Code Point (DSCP) Flow Ctrl
UnusedIP Precedence
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 19
IP Precedence and DSCP Compatibility
Compatibility with current IP precedence usage (RFC 1812)
Differentiates probability of timely forwarding:(xyz000) >= (abc000) if xyz > abc(that is, if a packet has DSCP value of 011000, it has a greater probability of timely forwarding than a packet with DSCP value of 001000)
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 20
Per-Hop Behaviors
DSCP selects PHB throughout the network:
Default PHB (FIFO, tail drop)
EF PHB
AF PHB
Class-selector PHB (IP precedence)
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 21
EF PHB
EF PHB:
Ensures a minimum departure rate
Guarantees bandwidth—class guaranteed an amount of bandwidth with prioritized forwarding
Polices bandwidth—class not allowed to exceed the guaranteed amount (excess traffic is dropped)
DSCP value of 101110: Looks like IP precedence 5 to non-DiffServ-compliant devices:
Bits 5 to 7: 101 = 5 (same 3 bits are used for IP precedence)
Bits 3 and 4: 11 = No drop probability
Bit 2: Just 0
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 22
AF PHB
AF PHB:
Guarantees bandwidth
Allows access to extra bandwidth, if available
Four standard classes: AF1, AF2, AF3, and AF4
DSCP value range of aaadd0:
aaa is a binary value of the class
dd is drop probability
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 23
AF PHB (Cont.)
Each AF class uses three DSCP values.
Each AF class is independently forwarded with its guaranteed bandwidth.
Congestion avoidance is used within each class to prevent congestion within the class.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 24
AF PHB (Cont.)
Each AF class uses three DSCP values.
Each AF class is independently forwarded with its guaranteed bandwidth.
Congestion avoidance is used within each class to prevent congestion within the class.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 25
DSCP Summary
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 26
Enabling QoS in the Campus
ApplicationL3 Classification
DSCPPHBIPP CoS
Transactional Data 18AF212 2
Call Signaling 24CS3*3 3
Streaming Video 32CS44 4
Video Conferencing 34AF414 4
Voice 46EF5 5
Network Management 16CS22 2
L2
Bulk Data 10AF111 1
Scavenger 8CS11 1
Best Effort 000 0
Routing 48CS66 6
Mission-Critical Data 26AF31*3 3
Classification and Marking Cisco Marking Recommendations
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 27
SiSi SiSi
SiSiSiSi
Access
Distribution
Core
Enabling QoS in the Campus Congestion Scenario: TCP Traffic Burst + VoIP
Typical 20:1
Data Over-
Subscription
Typical 4:1
Data Over-
Subscription
= Data
= Voice
Instantaneous
Interface
Congestion
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 28
Enabling QoS in the Campus Congestion Scenario: Data + VoIP
P0
P1P2
Voice
Max. 80 Kbps
PC
AccessSwitch
IP PhoneEnclosure
Integrated
3-Port Switch
Phone
Data
Max. 100 Mbps
During Data Traffic Bursts, Buffers Can Become Congested, Causing Voice Packets to Be Dropped
P
Potential
Congestion Points
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 29
Enabling QoS in the Campus Scheduling in IP Phones
Voice media traffic is marked with CoS 5/ DSCP EF (high priority)
Data traffic from the PC is remarked with CoS 0 (low priority) by the IP phone switch; this occurs if PC tags frames as 802.1p/Q; phone switch transparent if PC frames untagged
P0P1
Priority Q
Data Qs
P2
Voice
CoS = 5CoS = 5
DataCoS = 0
P1 Untrusted:
Phone Switch
Rewrites CoS = 0
PC
Access
Switch
IP Phone Enclosure
Phone
P
P Trusted:
Switch Accepts
incoming CoS
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 30
Campus QoS ConsiderationsEstablishing Trust Boundaries
1 Optimal Trust Boundary: Trusted Endpoint
A device is trusted if it correctly classifies packets
3 Suboptimal Trust Boundary
Only use if access switch cannot perform classification
2 Optimal Trust Boundary: Untrusted Endpoint
SiSi
Endpoints Access Distribution Core WAN Aggregators
Trust Boundary
1
2
3
SiSiSiSiSiSi SiSiSiSiSiSi
SiSiSiSiSiSi
For scalability, classification should be done as close to the edge as possible
The outermost trusted devices represent the trust boundary
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 31
Network Infrastructure Agenda
Building a Campus Network
QoS in the Campus
QoS in the WAN
Qos in the Wireless LANs
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 32
Enabling QoS in the WAN
Loss DelayDelay
Variation(Jitter)
Factors That Negatively Affect Packet-Based Voice/Video
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 33
Types of Delay
Processing Delay: The time it takes for a router to take the packet from an input interface, examine it, and put it into the output queue of the output interface
Queuing Delay: The time a packet resides in the output queue of a router
Serialization Delay: The time it takes to place the ―bits on the wire‖
Propagation Delay: The time it takes to transmit a packet
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 34
Processing and Queuing Delay
Processing Delay: The time it takes for a router to take the packet from an input interface, examine it, and put it into the output queue of the output interface
Queuing Delay: The time a packets resides in the output queue of a router
Serialization Delay: The time it takes to place the ―bits on the wire‖
Propagation Delay: The time it takes to transmit a packet
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 35
Ways to Reduce Delay
Upgrade the link; the best solution but also the most expensive.
Forward the important packets first.
Compress the payload of Layer 2 frames (it takes time).
Compress IP packet headers.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 36
Packet Loss
Tail drops occur when the output queue is full. These are common drops, which happen when a link is congested.
Many other types of drops exist, usually the result of router congestion, that are uncommon and may require a hardware upgrade (input drop, ignore, overrun, frame errors).
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 37
Ways to Prevent Packet Loss
Upgrade the link; the best solution but also the most expensive.
Guarantee enough bandwidth to sensitive packets.
Prevent congestion by randomly dropping less important packets before congestion occurs.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 38
Traffic Policing and Shaping Overview
These mechanisms must classify packets before policing or shaping the traffic rate.
Traffic policing typically drops or marks excess traffic to stay within a traffic rate limit.
Traffic shaping queues excess packets to stay within the desired traffic rate.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 39
Traffic Policing and Shaping Overview
These mechanisms must classify packets before policing or shaping the traffic rate.
Traffic policing typically drops or marks excess traffic to stay within a traffic rate limit.
Traffic shaping queues excess packets to stay within the desired traffic rate.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 40
Policing vs. Shaping
• Incoming and outgoing directions.
• Out-of-profile packets are dropped.
• Dropping causes TCP retransmits.
• Policing supports packet marking orre-marking.
• Outgoing direction only.
• Out-of-profile packets are queued until a buffer gets full.
• Buffering minimizes TCP retransmits.
• Marking or re-marking not supported.
• Shaping supports interaction with Frame Relay congestion indication.
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 41
Enabling QoS in the WANLink Fragmentation and Interleaving (LFI)
64
Bytes
8 ms
4 ms
2 ms
1 ms
640Used
Serialization Delay Matrix
56 kbps 9 ms
64 kbps
128 kbps
256 kbps
512 kbps
768 kbps
128
Bytes
256
Bytes
512
Bytes
1024
Bytes
1500
Bytes
16 ms
8 ms
4 ms
2 ms
1.2 ms
18 ms
32 ms
16 ms
8 ms
4 ms
2.6 ms
36 ms
64 ms
32 ms
16 ms
8 ms
5 ms
72 ms
128 ms
64 ms
32 ms
16 ms
10 ms
144 ms
187 ms
93 ms
46 ms
23 ms
15 ms
214 ms
FragmentationSize Matrix
(Based on 10-msec Delay)
Frag
Size
80 Bytes
160 Bytes
320 Bytes
640 Bytes
1000 Bytes
56 kbps 70 Bytes
64 kbps
128 kbps
256 kbps
512 kbps
768 kbps
PVC
Speed
2000 Bytes1536 kbps X
Fragment-Size Recommendations
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 42
Voice
Interleave
WFQ
Link Fragmentation
and Interleave
Low Latency Queuing
PacketsOut
PacketsIn
Police
Video
Enabling QoS in the WANScheduling in the WAN
Best Effort
Signaling
TXRing
Critical Data
Layer 3 Queuing Subsystem Layer 2 Queuing Subsystem
PQ
PQ Packets Do not Go Through Fragmentation:
on Low-Link Speeds, You Cannot put Large
(i.e., Video) Packets in the PQ with Voice Packets
Therefore video traffic not recommended for link
speeds <768kbps
CBWFQ Fragment
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 43
4/5 Class Model
Scavenger
Critical Data
Call Signaling
Best Effort
Realtime
How Many Classes of Service Do I Need?Expanding the Number of Classes of Service over Time
8 Class Model
Critical Data
Video
Call Signaling
Best Effort
Voice
Bulk Data
Network Control
Scavenger
11 Class Model
Network Management
Call Signaling
Streaming Video
Transactional Data
Interactive-Video
Voice
Best Effort
IP Routing
Mission-Critical Data
Scavenger
Bulk Data
Time
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 44
cRTP
Header
~2-4 Bytes
Enabling QoS in the WANProvisioning Bandwidth with Compressed RTP (cRTP)
Compresses RTP + UDP + IP headers (40 bytes) down to2–4 bytes
Enabled on a per-link basis
LinkHeader
IP HeaderUDP
HeaderRTP
Header
VoIP Packet
X Bytes20 Bytes8 Bytes12 Bytes
Voice Payload
X Bytes
CodecPPP
6 Bytes of Header
ATM
53 Bytes Cells with
a 48-Byte Payload
Frame-Relay
4 Bytes of Header
G.711 at 50 pps 68 kbps 85 kbps 67 kbps
66 kbps 84 kbps
12 kbps 21.2 kbps
G.711 at 33 pps
G.729A at 50 pps
G.729A at 33 pps 10.5 kbps 14 kbps
65.5 kbps
11.2 kbps
10 kbps
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 45
Enabling QoS in the WANA Day in the Life of a VoIP Packet: Without cRTP
Packet
Size (Bytes)
Frame
Relay
Payload
(20)
Assumption:
G.729, 20-ms Sample
Payload = 20 Bytes
20
60
78
64
Payload
(20)
Payload
(20)
F/R (4)
RTP (12)
IP (20)
UDP (8)
802.1Q (4)
Enet (14)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
802.1Q (4)
Enet (14)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
Payload
(20)
78
60
20
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 46
cRTP Is
Point to
Point
Enabling QoS in the WANA Day in the Life of a VoIP Packet: With cRTP
cRTP Is not Free!
Watch for CPU on
WAN Edge Routers!!!
Payload
(20)
Assumption:
G.729, 20-ms Sample
Payload = 20 Bytes
Frame
Relay
F/R (4)
Payload
(20)
cRTP (4)
Packet
Size (Bytes)
20
60
Payload
(20)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
802.1Q (4)
Enet (14)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
802.1Q (4)
Enet (14)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
Payload
(20)
RTP (12)
IP (20)
UDP (8)
Payload
(20)
78
60
20
28
78
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 47
Network Infrastructure Agenda
Building a Campus Network
QoS in the Campus
QoS in the WAN
Qos in the Wireless LANs
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 48
WLAN and LAN
Wireless LAN (WLAN) as an extension to wired LAN
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 49
WLAN QoS Queuing Overview
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 50
WLAN QoS RF Backoff Timing
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 51
WLAN QoS Queuing Overview
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 52
What We Have Built So Far
Network InfrastructureDistribution/
Core SwitchCampus
BranchWAN Aggregation
Router
BranchRouter
IP WAN
AccessSwitch
AccessSwitch
SiSi
SiSi
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Confidential
Session ID
Presentation_ID 53