Application > Frame Relay

This requires installation of the Frame Relay option.

Frame relay is a WAN (Wide Area Network) protocol that operates at the physical and data link layers of the OSI (Open systems Interconnection) reference model. Frame relay is a packet-switched technology. Packet-switched networks enable end stations to dynamically share the network medium and the available bandwidth. Variable-length packets are used for more efficient and flexible transfers. These packets then are switched between the various network segments until the destination is reached.

Frame relay virtual circuits are identified by DLCIs (Data-Link Connection Identifiers). The DLCI values typically are assigned by the Frame relay service provider. Frame relay DLCIs have local significance, which means that the values themselves are not unique in the Frame relay WAN. Two DTE devices connected by a virtual circuit, may use a differ-ent DLCI value to refer to the same connection.

Local Management Interface (LMI), the LMI is a set of enhancements to the basic Frame relay specification for management applications.

4.11.1 Frame Relay

Selecting the Frame Relay tab from the Interface folder will launch the Frame relay setup screen shown in Fig. 4.80.

Fig. 4.80 Frame Relay screen.

4.11 Application > Frame Relay

Interface Press the Interface menu field to select between None, PRI (2 Mbps) or V-series interface to be used on the frame relay.

Mode Select how the receiver(s) and transmitter(s) are used.

To the right of the interface selection it is indicated which of TxA, RxA and RxB that are activated for the selected mode.

Frame header size Use the Frame header size menu field to set the frame header size (in bytes). A size between 2 and 4 is selectable; 2 is normally used.

Press Frame header size menu field - to open the setup menu screen.

Max. frame size Use the Max. frame size field menu to set the maximum size (in bytes) of any frame. A size between 20 and 4093 can be selected. This size does not include the FCS field. Max. frame size is used for identifying “Long Frames”.

Press Max. frame size menu field - to open the setup menu screen for this purpose.

LMI type Press the LMI type field and use the drop-down menu to select how the LMI type is carried out.

Selecting Auto will make the CMA 3000 detect the type automatically.

Choosing Q.933 Annex-A, T1.617 Annex-D and Original FRF will carry out the LMI type in accordance to the respective recommendations.

Press the adjacent LMI type field and use this drop-down menu to choose either UNI Terminal, UNI Network or NNI,

Heart beat interval (Emulate mode only)

Use the Heart beat interval menu field to set the period (in seconds) be-tween LMI frames. Select period bebe-tween 2 and 40 seconds.

Press Heart beat interval menu field - to open the setup menu screen for this purpose.

Full status rate (Emulate mode only)

Use the Heart beat interval menu field to set the full status rate. Set value between 1 and 255.

Press Full status rate menu field - to open the setup menu screen for this purpose.

Monitor This mode uses two receivers for monitoring line traffic.

Emulate This mode uses receiver RxA and transmitter TxA for testing a frame relay connection.

Control bits (Emulate mode only)

Press each of the Specific Control bits to set the value of the auxiliary bits in the frame header.

Press the control bit you want to change. This will toggle the binary value from 0 (zero) to 1, or vice versa.

Time slots Press the Time slots field menu and select the time slots on which to use frame relay.

Fig. 4.81 Timeslot.

Frame Relay Chan-nel Scanning

In typical GPRS implementations the Gb interface is a 2 Mbit/s line car-rying several frame relay connections. Each frame relay connection con-sists of a number of time slots. CMA 3000 provides a search facility which analyses the contents of a monitored 2 Mbit/s line and identifies the frame relay connections on the line. Hereby the user will get the essential information on the configuration of the Gb interface.

Scan: During the Frame Relay channel scan the above display shows the current estimate. The longer the scan runs, the more reliable the result will be.When the user stops the scan, the identified Frame Relay chan-nels are presented one by one. The user can the choose the channel to be used for Gb interface protocol analysis (an additional option required).

4.11 Application > Frame Relay

4.11.2 Frame Relay BERT Load

Selecting the Frame relay BERT load tab from the Frame relay folder will launch the screen shown in Fig. 4.82. The screen contains additional set-up parameters for the Frame relay option.

Fig. 4.82 Frame relay BERT load screen launched.

Pattern type Press the Pattern type field menu and select a pattern type from the drop-down menu.

Press the adjacent field menu and select whether the pattern to be Nor-mal or Inverted.

User pattern Press the User pattern field menu and set the user-defined pattern.

When clicking the digit the binary value will toggle from 0 (zero) to 1 or vice versa.

Receive pattern Press the Receive pattern field menu to activate (On) or deactivate (Off) the receive pattern detection.

Setting Receive pattern to Off it is possible to start the Frame Relay em-ulation with a payload, without starting a BERT measurement at the same time.

Sequence number-ing

Press the Sequence numbering field menu and enable the instrument to detect sequence errors in the received frames (On) or disable this func-tion (Off).

Receive DLCI Press the Receive DLCI field to open the setup screen - and use this menu to determine where the pattern is received. It is possible to setup values between 0 and 1023.

Transmit DLCI Press the Transmit DLCI field to open the setup screen - and use this menu to determine where the pattern is transmitted. It is possible to setup values between 0 and 1023.

Receive and Transmit DLCI has to match the DLCI of the frame relay channel to be tested.

Frame size Press the Frame size field to open the setup screen - and use this menu to set the values for the minimum and maximum frame sizes. It is possi-ble to set minimum and maximum size values from 20 to 4093.

Burst length Press the Burst length field to open the setup screen - and use this menu to set the length i.e., number of frames per burst. Possible burst length is selectable from 1 to 255 frames.

Utilization Press the Utilization field to open the setup screen - and use this menu to set the utilization, i.e., percentage of available bandwidth. Possible uti-lization is selectable from 1 to 100 percent.

Error Insertion Press the Error Insertion field menu and set the error insertion rate from the launched drop-down menu.

Error destination Press the Error destination field menu and select the destination for the error insertion from the launched drop-down menu.

Burst length Press error Burst length field to open the setup screen - and use this menu to set the number of sequential frames that are errored. Possible burst length is selectable from 1 to 255 frames.

Error insertion can also be activated in the Application/Stimuli pop-up.

Off No error insertion.

Manual Manually triggered inserts when pressing the (ERROR) key locat-ed on the front panel.

Burst*, Select between *10E-03, *10E-04, *10E-05, *10E-06, *10E-07

ES Errored Seconds

SES Severe Errored Seconds

4.11 Application > Frame Relay

4.11.3 DLCI Statistics

From the DLCI statistics screen found in the section 4.11, Application >

Frame Relay folder it is possible to setup the interval measurement. The statistics recording contains up to eight individual DLCI counters. While all are counted on totals, two of these are counted on interval basis that allows histogram presentation and general inspection of interval results.

The DLCIs with interval information are marked with a (*).

Counters that are not set beforehand are considered as 'free' and will be assigned to values encountered during the measurement.

Fig. 4.83 DLCI statistics setup screen launched.

4.11.4 CIR Test

The CIR, Committed Information Rate is a part of the agreement be-tween the customer and the Frame Relay network operator. It is ex-pressed through the parameter Bc (Burst committed) - the number of bits the network agrees to transmit over an interval (Tc). If more than the agreed number of the bits are sent the related frames must be marked (by setting the DE bit), so the network will know that the first frames might be discarded in case of congestion. Through the inspection of frames with this set over a period (Tc), the instrument can estimate the CIR.

In order to enforce this situation, the instrument can be set to generate traffic at higher and higher rates. If a far-end loop back is established the instrument can estimate the CIR. Select CIR Test from the Application folder to launch the screen shown in Fig. 4.84. The CIR Test screen is divided into to parts - a setup part and a result part.

Fig. 4.84 CIR Test screen.

4.11.5 CIR Test Setup Part

This contains the programming of the increased traffic load and the other parameters for the CIR Test.

Receive DLCI Press the Receive DLCI field and use the launched key pad menu to de-fine the DLCI value, where the pattern is received. Acceptable values be-tween 0 and 1023, when Frame Header size is 2 (see section 4.11.1,

4.11 Application > Frame Relay

Transmit DLCI Press the Transmit DLCI field and use the launched key pad menu to de-fine the DLCI value, where the pattern is received. Acceptable values be-tween 0 and 1023, when Frame Header size is 2 (see section 4.11.1, Frame Relay).

Frame size Press the first part of the Frame size field to set the minimum value in the frame size interval.

Press the second part of the Frame size field to set the maximum value in the frame size interval.

Burst length Press the Burst length field and use the launched key pad menu to set the burst length, i.e. number of frames per burst.

Utilization Press the Utilization field and use the launched key pad menu to set the utilization, i.e. percentage of available bandwidth.

Increment traffic load

Press the Increment traffic loadto increase the traffic load per each Tc period. Value is indicated in percentage.

Tc period Press the Tc period field and select the length of the Tc period from the launched drop-down menu.

Free-run Press the Free-run field to determine whether the CIR test is running con-tinuously or stops after the first run.

Start test Pressing the [Start test] softkey, will start the CIR test - and present the results of this test in the right side of the screen.

4.11.6 CIR Test Result Part

The right side of the screen is dedicated the results of the CIR Test.

Received Frames This field presents the total number of frames, received during the test.

CIR (bps) This field presents the estimated CIR.

Approx. Bc This field presents the estimated Burst, committed.

Approx. Be This field presents the estimated Burst, excess.

Maximal Through-put (bps)

This field presents the maximal throughput during the test.

4.11.7 Ping Test

Ping Test is a feature, that tests IP over frame relay by sending out test messages (ICMP - Internet Control Messages Protocol) that will be re-turned to the instrument under normal circumstances.

Select Ping test from the Application folder to launch the Ping test setup screen shown in Fig. 4.85.

Fig. 4.85 The Ping Test setup screen.

4.11.8 Ping Test Setup

The left part of the screen is dedicated the setup of the Ping Test.

Receive DLCI Press the Receive DLCI field and use the launched screen to set the DLCI value, i.e. where the ping is to be received. A value between 0 and 1023 can be selected, when Frame Header size is 2 (see section 4.11.1, Frame Relay).

Transmit DLCI Press the Transmit DLCI field and use the launched screen to set the DLCI value, i.e. where the ping is to be received. A value between 0 and 1023 can be selected, when Frame Header size is 2 (see section 4.11.1, Frame Relay).

4.11 Application > Frame Relay

Encapsulation Use this drop-down menu to select the IP encapsulation. The following encapsulations can be selected:

Source IP address Press the Source IP address field and use the launched key pad menu to set the source IP address. Acceptable address range between 1.0.0.0 and 255.255.255.255.

Dest. IP address Press the Dest. IP address field and use the launched key pad menu to set the destination IP address. Acceptable address range between 1.0.0.0 and 255.255.255.255.

Start Test Press the [Start Test] softkey to activate the test.

InARP Press the [InARP] softkey to initiate the InARP function.

The Frame relay test supports InARP (Inverse Address Resolution Pro-tocol). InARP permits a frame relay terminal to identify the IP address as-sociated with the DLCI. Through the LMI information the frame relay terminal can identify new virtual circuits represented by their DLCI val-ues. If the virtual circuit is used for IP, the associated IP address is not immediately available in the virtual circuit. By sending an InARP mes-sage (a “who-are-you” request) down the line, the far end IP device will respond with its IP address, and hereby give the necessary information to enable the IP service over the frame relay circuit.

The InARP test is enabled in the Ping Test screen. The returned IP ad-dress will be shown as the Dest. IP adad-dress, as well as respond to the received InARP requests. As IP address it will give the Source IP ad-dress.

Stop Test Press the [Stop Test] softkey to deactivate the test.

4.11.9 Ping Test Result

The right side of the screen is dedicated the results of the Ping Test.

Send ICMP echo... Presents the count of send ICMP echo frames.

Lost ICMP echo... Presents the count of lost ICMP echo frames.

Bad ICMP echo... Presents the count of mis-sequenced or duplicated ICMP echo frames.

Min. delay Presents the minimum round trip delay, since the start of the test.

RFC1490 IETF encapsulation according to RFC1490.

RFC1490/SNAP IETF encapsulation with SNAP, according to RFC1490.

Cisco proprietary Cisco proprietary encapsulation.

Max. delay Presents the maximum round trip delay, since the start of the test.

Average delay Presents the average round trip delay, since the start of the test.