Running Avaya Voice over Cisco Data: Keys to Success

Running Avaya Voice over
Cisco Data: Keys to Success
Paul Blakie - Senior Systems Engineer
Cross

Agenda
• Planning for VoIP
• Designing the network solution
• Best Practices

Network Types
• Circuit vs. Packet Switched Networks
– Circuit – Dedicated Bandwidth, Fixed Path
– Packet – Shared Bandwidth, Multiple Paths
• Convergence
– Single Network, Multiple uses
• Voice is an Application
– Applications ride on Infrastructure

Planning
• Why VoIP
– Cost Savings Toll Bypass Applications!
– Converged infrastructure
• VoIP vs. IP Telephony
• Why the distinction

• Know your network
Planning
– Monitoring tools
• Netflow
• NBAR
•MRTG
• Packet Analyzer
– Application analysis
• Know types and criticality
– Physical plant and cable
• Cat5e/Cat6
• Fiber optic

Agenda
• Planning for VoIP
• Designing the network solution
• Best Practices

Design
• It’s not about the
bandwidth
• Hardware Design
– Return of the Hierarchical
Design Model

• Equipment
• Currently Shipping:
Design
– Workgroup Switches
• 3560, 3750 (10/100, 10/100/1000, PoE, 32/64 Gbps Stack, 1/10 Gig
Uplinks)
– Core/Distribution Switches
• 4500 (3 to 10 slots, 10/100, 10/100/1000, PoE, 64 to 136 Gbps
Backplane)
• 6500 (3 to 13 slots, 10/100, 10/100/1000, PoE, 32 to 720 Gbps
Backplane)
• Legacy switches:
– 3550, 3500 XL, 2900XL, 4000
– 4500/6500 with older Supervisor engines

• Equipment
Design
– Power concerns
• How to power phones
– PoE switch
– Power brick
– In-line patch panel
• Power Budget
– IOS Differences (power inline auto, power inline
consumption)
• 802.3af vs. Cisco legacy power

• Logical Design
Design
– VLANs, VLANs, VLANs
– Separate Voice from Data
• Use separate LAN’s to reduce broadcast traffic. Avaya
recommends that broadcasts on a Voice subnet be
limited to 500-1000 broadcasts per second.
• Use VLAN’s and Layer-3 switching
– Cisco Discovery Protocol (CDP)
• Is it necessary
• Security Risk
• On or Off

• Logical Design
Design
– Single wire to the cube (Piggyback phone/PC)
• Trunk or non-trunk
• Switchport Mode Access or Switchport Mode Trunk
– voice vlan or auxiliary vlan (spoofed .1q)
• Ensure settings between phone and switch match

• Logical Design
Design
– Proper configuration of speed and duplex.
• Speed can be sensed, duplex setting is negotiated.
• Device with fixed speed/duplex connected to autonegotiation
device
– Auto-negotiating device can sense device’s speed
and match it.
– Auto-negotiating device cannot negotiate duplex.
Default to Half-duplex
– Follow manufacturer best practices for device settings

• Logical Design
Design
– Quality of Service (QoS)
• Anywhere there is oversubscription, network boundary,
or application inspection, congestion management is
needed. (End to End QoS)
• Layer 2 vs. Layer 3
–DSCP
– 802.1Q/p
• Trust boundaries (mls qos trust cos/dscp)
• Port based QoS should be avoided (ACLs can negatively
effect traffic performance)

Design
Quality of Service
Recommended Traffic Type
Layer
2 CoS
Layer 3 IP
Precedence
Class
Selector
Code-
Point
Layer 3
DSCP
Decimal
Number
DSCP
Binary
Provider A
MPLS
Provider B
MPLS
Provider C
MPLS
Reserved
7
7 network
CS7
-
(56)
Reserved
6
6 internet
CS6
-
(48)
Voice
5
5 critical
CS5
EF
(46)
101110
Real Time
Real Time
Real Time
Videoconferencing
4
4 flash-override
CS4
AF41
(34)
100010
Enhanced
Call Control
3
3 flash
CS3
AF31
(26)
011010
Interactive
Bursty-Hi
Critical
High Priority Data/Streaming Video
2
2 immediate
CS2
AF21
(18)
010010
Interactive
Bursty-Lo
Standard Business
Medium Priority Data
1
1 priority
CS1
AF11
(10)
001010
Non-Critical
Best Effort Data
0
0 routine
BE
(0)
Best Effort
Best Effort
General

Design
• Critical Infrastructure
– Services – DHCP, DNS, TFTP, HTTP
– DHCP
• Option 176/242
• Old Phones (End of Sale/Support) that use 176: 4606,
4612, and 4624.
• Current phones (use 176): 4602, 4610, 4620, 4621,
4622, 4625
• New Series (use 242): 9610, 9620, 9630, 9640, and
9650
• Redundancy (Centralized or Distributed servers)
• Change from default manual on each phone
– DNS
• The debate…

Design
• Critical Infrastructure
– TFTP
• Unreliable
• Service or Application
– HTTP/HTTPS
• Reliable
• Scalable
• Old Phones: ONLY use TFTP. Being end of support,
there is no new firmware to change this.
• Current phones: Use both. It starts looking for HTTP,
then will settle for TFTP if needed.
• New Series: ONLY use HTTP. No option for TFTP.

Design
• VoIP Performance Measures
– Max packet network delay: One-way Between endpoints
80 ms (millisecond) delay or less can, but may not, yield toll quality
80ms-180ms delay can give business communication quality
greater than 180ms may be acceptable depending on customer
expectations
– Max packet jitter: Jitter is a measure of the variability of delay Between
Endpoints
Toll quality is an average jitter of less than 20ms
– Max packet loss: Loss Between Endpoints
1% or less can yield toll quality
3% or less can provide Business communication quality
greater than 3% may be acceptable for voice”

Design
•CODEC Choice
•Use Appropriate CODEC for needs
•Use G.711 for LAN (Don’t use Silence Suppression)
•Use G.729 for limited bandwidth WAN (Don’t use Silence
Suppression- use G.729B instead)
•Actual Bandwidth
•There are great calculators available online, but here are some
estimates. Lots of variables that will change these numbers
(fragmentation, encapsulation, etc).
•G.711 (20ms Packet) over Ethernet=90.4kbps
•G.711 (20ms Packet) over PPP=82.8kbps
•G.729 (20ms Packet) over Ethernet=34.4kbps
•G.729 (20ms Packet) over PPP=26.8kbps

Design
Voice CODEC Selection
Ethernet BW
Codec
Data
Rate
Packet
Size
Voice
Sample
IP
BW
On the
Wire
On the
Wire +
802.1Q
FR
BW
ATM
AAL5
BW
PPP
BW
kbps
Bytes
ms
Kbps
Kbps
Kbps
Kbps
Kbps
Kbps
G.711
64
20
160
80.0
88.0
88.8
82.4
106.0
83.2
G.726
40
10
50
72.0
88.0
89.6
76.8
127.2
78.4
G.729 / (a)
8
20
20
24.0
32.0
32.8
26.4
42.4
27.2
G.723
5.3
30
20
16.0
21.3
21.9
17.6
28.3
18.1

Design
• Possible reasons for needing different IP Network
Regions
• One group of endpoints requires a different codec set than another group –
based on bandwidth or encryption needs
• Calls between separate groups of endpoints require a different codec set
than calls within a single group of endpoints, again based on requirements
related to bandwidth or encryption.
• Specific C-LAN or MedPro or other resources must be accessible to only a
specific group of endpoints.
• Groups of endpoints may have different Shuffling needs
• One group of endpoints requires a different UDP port range or QoS
parameters than another group.
• One group of endpoints reports to a different VoIP Monitoring Manager
server than another group.

Design
• Firewall Considerations
• If you are filtering packets between the phones and
the gateway (MedPro/CLAN), make sure to allow the
following
– UDP port 1719 to the CLAN(s) for Endpoint Registration
– TCP port 1720 to the CLAN(s) for H.225 Call Signaling
– UDP port range specified in Network Region Screen to the
MedPro(s).
– Standard ports to various servers (as required)
• TLS – TCP 411
• HTTP - TCP 80-81
• TFTP – Use Layer 3 since L4 ports tend to be random

Agenda
• Planning for VoIP
• Designing the network solution
• Best Practices

Best Practices
• Communicate, Communicate, Communicate
• Perform VoIP Readiness Assessment
• Physical Layer
– Map your cable plant, and keep a current Visio of the
logical and physical design.
• IPSec VPNs
– Don’t discount the Internet, but don’t rely on it.
– Use it where it makes sense

• Switches
Best Practices
– Speed Duplex
• Switch to switch – manually set
• Switch to desktop/phone – auto (test in your
environment)
• Switch to telephony device (call server,MED Pro, CLAN)
– set 100/full Trunk/Non Trunk
• Verify switch tagging/trunking settings

Best Practices
• Critical/intelligent infrastructure and services
– DNS, DHCP. TFTP, HTTP
• Plan for worst case traffic volume
• Add redundancy where possible
– QOS
• Verify QOS settings match for all CoS, DSCP mappings
• Verify “choke point” prioritization mechanisms
–UPS
• Checked your batteries recently
– Network Monitoring
• If you’re driving blindfolded through a tunnel, why would
you be surprised when you hit a wall

Contact us For all of Your Voice and Data
Communication Needs
Cross Telecom Corporation
Website: www.crosstelecom.com
Toll Free: 866-983-3500