Research and evaluate the range of issues that are likely to occur within a converged network environment.

A converged network is defined as : A single network with the capacity to carry a combination of data, voice and video traffic.(Global Knowledge , 2010). Data and Voice/Video have very different needs from the network, data needs acknowledgement that data has arrived i.e. (TCP) , Voice/Video don't need all the data but need data at the right time to output sound/images in real time i.e. (UDP).

Why do businesses want a single network?

According to “How does network convergence support a business strategy?”, Cisco, (2003) pg9) the main benefits of a converged network with examples in Santander are:

1. Cost reduction and management - WAN network costs are decreased because two i.e. (one main and one backup connection) lines, instead 100's of phone lines via PABX , can be used between office locations, making it easy to switch between ISP's (Internet Service Provider) forcing them to compete with each other.

2. Property and facilities utilisation and management - Network management responsibility is passed onto Santander. Data, Voice and Video network traffic now have to be routed, sorted and managed internally.

3. Organisational agility - IT staff can now service changes and problems on site were before one would have to wait for a ISP technicians.

4. Employee productivity - office works have an array of tools that are now integrated allowing workers to share screen informations while talking over video conference improving employee productivity. However According to ZDNET(2010) 90% of security threats come from employees.

So there are two main issues from these benefits which are, X now needs to manage network traffic and security.

How do network administrators manage traffic?

The tool used to manage these different network needs is known as QOS (Quality of Service) which provides the ability to provide different data flows. There are three main factors in QOS → Delay i.e. (time taken by packet to destination from A to B) , Jitter I.e (time to destination between packet A and B) and bit rate.

The bellow table summarizes the differences between Video, Voice and Data:

	Video	Voice	Data
Example	Video Conference	VOIP phone	FTP(File transfer protocol)
Packet size	+-256 – 1518 bytes	+-180 bytes	+-512 I.e.(greater if reset MTU (Minimum transmission unit))
Maximum Delay	If video stream up to 3 minutes if conference +-150 ms	+-150 ms	Not greater than packet TTL (Time to live
Loss Sensitive	No,but effect quality of video.	No, but effect quality of voice.	Yes, Corrupting files
Jitter Sensitive	Yes,effect quality of video.	Yes,effect quality of voice.	No
Bit rate	64kbps	16 kbps	Depend on file size
Transport	UDP	UDP	TCP
COS and/or TOS (Precedence bits)	Example: Bits 100 → 4 (High priority)	Example: Bits 010 → 2 (Medium priority)	Example: Bits 001 → 1(Low priority)
Table: QOS - Video, Voice and Data (Cisco, 2010), (Wikipedia, 2010)

Queues are used to prioritised traffic with Qos markings. In the DSCP (differentiated services code point) standard within Ipv4 there are two fields in the IP header, COS(Class of Service) → ISO layer 2 marker, and TOS (Type of Service) → ISO layer 3 marker.

In the LAN environment COS is used to prioritise traffic that is going to a workstation with PC and VOIP. These two types of traffic may be carried over two separate VLAN´s, with many small UDP VOIP and some large TCP application packets. A PC application might mark its own packets with COS values e.g. (bits 101 → 5) that are higher priority than the VOIP packets thereby effecting VOIP packets and reducing Voice quality.

In a WAN environment where COS values are replicated in TOS, WAN connectivity and data rates have to be guaranteed through SLA (Service Level agreements) as QOS can only guarantee QOS up until the network edge provided there is no LAN congestion.

The highest priority (bits 111 → 7) are reserved for routing packets. Why?. Without routing packets routing table would never be able to be built i.e. (Unless you using static routes) making routing impossible!!

EXAMPLE PROBLEM: The above table classification classifies data as the lowest priority but this is not always what is needed. In X daily batch files are sent with financial information that are of higher priority than Voice packets. The application that sends these batch files are allowed to apply there own COS priorities.

In a big bank like X there are hundreds of different types of applications which can't all be classified into only 6 categories. A alternative classification system of DSCP extends the TOS bits by three adding more room for classification.

How do network administrators manage security?

Moving to a single network gives more network management control to X enabling them to adapter quicker to changes in the business environment. Security has become an important topic, especially for banks.

LAN Switch-ports need to be configured as access, voice or trunk ports but this still doesn't stop VLAN hopping i.e. (the port might be configured as dynamic) . Switch-port violation configurations need to be set but can result in more calls to the IT department because interfaces have been disabled by security violations reducing employee productivity.

Other security mechanisms like dot1x authentication might not be possible because the application batch server might not support dot1x requiring forced-authentication. In the WAN environment VLAN trunks are not encrypted. This is seen as the job of other encapsulations such as IPSEC which provides a complete security tool set.

Conclusion

As more management and control of the networks moves over to X the list of services that can be supplied to employee workstation grows. The network becomes more adaptable to changes in the business network environment instead of the ISP network environment. Resulting in a network that that meets user expectation more closely.
Security and QOS have become key issues but have also created new ways of improving worker productivity through VOIP and Video Conferencing. Security was a huge unmanaged risk in the old network model with service providers out of touch with end users such as X.
X now has a network that is more important and services there needs more than ever. The single network helps X be a better bank.