Ethernet LANs and IP Office Networking

5 techniques to optimize and understand IP Office Networks

In this post, Ethernet LANs and IP Office Networking , see how to prepare your customer’s network to help optimize both the Avaya IP Office and the Customer’s LAN. Create network traffic rules to avoid loops, delay and collision in the voice and data networks. Finally, learn how the IP Office components orchestrate all of these components.

A few months ago, I was out helping a customer add IP Phones to a new building, connected back to the Core via Fiber connectors and Cisco switches. We ran into a couple of issues when connecting the phones and PCs back to the MDF.

Here, I share some of the best practices that helped us configure the network switches and adjust some parameters in the IP Office control unit.

5 techniques to optimize and understand IP Office Networks

• 1.- Interfaces and Signaling Protocol Overview
• 2.- IPO and Ethernet LANs interactions
• 3.- IP Office Port Speed and Duplex
• 4.- Voice Compression Channels
• 5.- Packet and Circuit Switching Mechanisms

1.- Interfaces and Signaling Overview

In order for you to configure, troubleshoot or prepare your network equipment to handle VoIP, there are a few things that you should be aware of. I have listed a couple of these items below:

Interfaces Overview – The IP Office comes with two physical ethernet ports that allows you to connect to two different networks sharing a single IP Office system providing communication and services to endpoints and other apps. The fact that we have two ports to choose from, gives us flexibility to connect and segregate a secure and not secured networks.

IP Office Ethernet Interfaces – LAN and LAN2 are the two physical Ethernet Interfaces that allows you to connect to external LAN/WAN devices. Both are Layer 3 capable of routing data based on its routing tables.

As a best practice, you would configure the SIP Trunk ITSP Uplink to LAN2 as a designated port to allow connectivity between the STUN Server and the IP Office bypassing the customer’s LAN.

Signaling Protocols

AVRIP= We can call this protocol Avaya-RIP, and it does work very similar to the RIP routing protocol, helping the IP Office systems send hello packets every 30 seconds with a max of 0.5. This signaling protocol updates the telephone lamps through port 50795.

H.225 – as part of the H.323 helps exchange user information through the VoIP media-stream exchanged between the endpoints and gatekeeper, in this case the IP Office.

H.245 – Once a call has been stablished through H.225, the H.245 takes over the media streams to enable video and voice transmission.

2.- IPO and Ethernet LANs interactions

The following are some explanation of how the IP Office can recover its original configuration through BootP and how VLANs can help prioritize the voice traffic with different tagging mechanisms.

The IP Office uses the Layer 2 Bootstrap protocol (Boot-P) in conjunction with IP-Broadcast to make possible the delivery of the main configuration file located in the Manager’s application working directory, in the case of it loosing the original configuration files. This process is used less after the introduction of internal SD cards with the IP500V2s.

VLANs and 802.1Q/P – By now, you know how important it is to setup trunking and access-ports configuration in your network switches to allow best effort and priority based on packet classification and tagging. By creating VLANs and configuring any of the tagging mechanism available, enhances the quality of the delivery of the voice-data-streams through the Ethernet LANs.

Policies and Queue Size Mechanisms – These mechanisms are part of the QoS (Diffserv value of 46 or EF) settings congestion-avoidance functionality that helps the routing queues behave in different ways depending on the mechanism implemented. Here I list a couple of them=

WWR (Weighted Round Robin) – This is a queue mechanism, which assigns weights or a queuing priority value to each connection, enabling traffic classification and prioritization with 802.1p.

CBWFQ – The Class-Based Weighted Fair Queuing allows you to set the transmission bit rate, size, and enable the L3-Switch/Router decide what to do, if the traffic exceeds the CBWFQ policy.

PQ – Priority Queuing – Is a congestion management mechanism that can be implemented with Cisco IOS Access-Lists to prioritize the voip streams based on priority with Cisco gear. Extreme switches calls it QoS Profiles. Refer to each vendor’s white-papers for more information.

Other protocols that you may want to learn or review

Spanning Tree or RSTP – It is a Layer 2 protocol that assigns a default priority of 32768 + to the Switch with the lowest MAC Address value to become the Root Bridge. This election is done via BPDU messages sent throughout the existing switches. The adjacent switch with the lower MAC will assume to be the Root Bridge until all of the BDPU multicast messages are sent among them, assigning the Root and Designated Ports, and finally avoiding loops by shutting down the second uplink port with a BPDU Guard, or by setting the port to Block state.

For other Avaya Media Gateways such as the MG430s, it is not recommended implementing STP or RSTP in any production network. The election of the Root Bridge might bring the network down. If you are really interested on running this protocol through the MGs, I suggest that you schedule downtime and allow all of the network components negotiate this election.

LACP (Etherchannel) is an aggregation mechanism to allow two switches to increase their speed throughput and fault tolerance allowing business continuity if one port/link fails.

3.- IP Office Port Speed and Duplex

Avaya goes back and forth on this. Legacy servers such as, the IP400-412 provides two Half-Duplex interfaces versus the Server Edition with a Gig-Speed, and finally  the IP500V2, which comes with two MDI auto-sensing Ethernet ports capable of running 10/100 Full-Duplex.

4.- Voice Compression Channels

For those IP Office implementations utilizing a mixed of phones (IP, SIP and TDM), Voice Compression Modules are introduced to help with the transcoding. The following are some of the steps taken when a VCM channel is be needed.

Analog to Analog

Digital to Digital

Analog to Digital

Digital to Analog

A VCM channel is used whenever an IP Station has to interact with Analog, Digital, Voicemail, and Conferencing Ports. Other considerations are= Call listen, intrusion, silent monitoring and call recording.

5.- Packet and Circuit Switching Mechanisms

For being a small IP-PBX system, this box can accomplish both of best worlds with Packet and Circuit switched private networks. A Private circuit-switched deployment can be accomplished through ISDN and T1 trunks; and when interconnecting the IP Office with your Data infrastructure, the Packet-Switched Private network is born. 

SIP Trunking, IP-DECT, and H.323 trunks incorporate a Packet-Switched network utilizing a Private Cloud network. This could be established through technologies such as VPN, PPP, MPLS, Metro-E, etc.

Before I let you go, let’s briefly talk about the TDM-BUS technology. – It allows the IP Office to produce tone through a Tone-Generator, as well as MOH. A conference Chip is used for Conference Meet-Me.

Decoding and encoding our voice utilizing the TDM Bus in conjunction with a VCM resource whenever an IP resource is utilized.

Question

Which methods do you use when first implementing VoIP?

Resources

VCM and Data Channels

HP Curve Avaya Config

Extreme with Avaya IP Phones – QoS Best Practices