Frame Aware DSU/CSU Product Comparison at TelephonyWorld.com

Frame Aware DSU/CSU Product Comparison
DSU Vendor	ADC Kentrox	ADTRAN	Digital Link	FrameSaver SLV	VISUAL
Monitoring Layer 1 & 2	Yes	Yes	Yes	Yes	Yes
Monitoring Layer 3	No	Yes	Yes*	Yes	Yes
Monitoring Layer 4 to 7	No	No	Yes*	Yes	Limited Layer 7
Packet Capture and Decode	No	No	Yes*	Yes*	Yes
RMON Compliant	No	No	4 Groups	Yes-7 Groups	Alarms Only
Dedicated Management PVC	Yes	Yes	No	Yes	Yes
Shared Management PVC	No	Yes	No	Yes	No
PVC Testing & Loopbacks	No	Yes	No	Yes	No
Automatic Latency Test	Yes	Yes	No	Yes	Command Only?
Actual Burst Analysis	No	Yes	No	Yes	1 Sec. Avg.
Actual Dropped Frames	No	Yes	No	Yes	No
Disaster Recovery	No	Yes	No	No	No
Datasheet	Click Here	Click Here	Click Here	Click Here	Click Here
List Price	$1,195 (56K) $3,095 (T1)	$895 (DSU IQ) $1,595 (TSU IQ)	$1,095 (56K) $1,799 (T1)	$1,095 (56K) $2,495 (T1)	$1,195 (56K) $3,495-6,495 (T1)

Data Reported March 1998, *Utilizes NetScout Probe, Quotes and Availability Call Toll Free 800-444-5851 or 214-503-7400.

The above matrix is a product comparison of high-end protocol aware DSU/CSUs provided for your convenience. Far more than a simple DSU, products in this matrix include specific features for frame relay applications such as performance and service level agreement monitoring, router independent connectivity, and PVC diagnostics. Corporate end-users who value these features will be running mission-critical applications and usually have a small staff overseeing their network management. Because the above products must meet the most exacting standards of Network Service Providers (NSPs) and large corporate end-users whose very business depends on their networks, they must be of the highest quality and, therefore, command a price premium.

What does it all mean?

The reference chart below describes in greater detail each layer in the OSI model and their respective functions.

OSI (Open System Interconnection) Model

Layer	Name	Function
7	Application Layer	Program-to-program communication. Provides interface to end-user processes. Provides standardized services to applications.
6	Presentation Layer	Manages data representation conversions. For example, the Presentation Layer would be responsible for converting from EBCDIC to ASCII. Specifies architecture-independent data transfer format. Encodes and decodes data; encrypts and decrypts data; compresses data.
5	Session Layer	Responsible for establishing and maintaining communications channels. In practice, this layer is often combined with the Transport Layer.
4	Transport Layer	Responsible for end-to-end integrity of data transmission. Manages network layer connections. Provides reliable packet delivery mechanism.
3	Network Layer	Routes data from one node to another. Addresses and routes packets.
2	Data Link Layer	Responsible for physically passing data from one node to another. Frames packets. Controls physical layer data flow.
1	Physical Layer	Manages putting data onto the network media and taking the data off. Interfaces between network medium and network devices. Defines electrical and mechanical characteristics.