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This chapter describes special features of the LightStream 1010 ATM switch software that are not commonly used, and includes the following sections:
You can select the criteria used to install frame discard on switched virtual circuits (SVCs). The default is to install packet discard based on the presence of the ATM adaptation layer 5 (AAL5) information element in the SETUP message.
You can use the global configuration function to modify the frame discard for all available bit rate (ABR) connections.
To configure frame discard, use the following command in global configuration mode:
| Command | Task |
|---|---|
Configure the SVC frame discard. |
This global configuration command changes the information that the switch uses to decide whether or not to install frame discard on SVCs. User-Network Interface (UNI) 4.0 signalling allows for explicit signalling of frame discard. Pre-UNI 4.0 versions use the presence of the AAL5 information elements to determine whether or not to install frame discard. If the AAL5 information element is present, frame discard is installed; otherwise it is not.
For example:
In the following example, the switch behavior is set to not use the AAL5 information element to dictate frame discard.
Switch(config)# no atm svc-frame-discard-on-aal5ie
To display the ATM frame discard configuration, use the following privileged EXEC command:
| Command | Task |
|---|---|
show running-config | Display the frame discard configuration. |
The following example shows how to display the frame discard configuration:
Switch# show running-config Switch# show running-config Building configuration... Current configuration: ! ! Last configuration change at 19:02:51 UTC Thu Feb 27 1997 ! version XX.X no service pad service udp-small-servers service tcp-small-servers ! hostname Switch ! boot bootldr bootflash:/tftpboot/rbhide/ls1010-wp-mz.112-1.4.WA3.0.15 ! network-clock-select 1 ATM0/0/0 network-clock-select 4 ATM0/0/0 ip host-routing no atm svc-frame-discard-on-aal5ie
Multipoint-to-point funnel signalling (funneling) merges multiple incoming SVCs into a single outgoing SVC. An incoming SVC is called a leaf SVC, and the outgoing SVC is called the funnel SVC. Funneling is supported on both feature card per-class queuing (FC-PCQ) and feature card per-flow queuing (FC-PFQ).
The LightStream 1010 ATM switch performs funnel switch merging on SVCs that originate from the UNI. With the exception of the LightStream 1010 ATM switch funnel switch (see Figure 18-1), the multipoint-to-point funnel appears to the network as a point-to-point connection.
Figure 18-1 illustrates multipoint-to-point funnel signalling.
Mulitpoint-to-point funnel signalling requires no configuration. For funneling to operate, traffic parameters must be the same for all the SVC leaves on a particular funnel call.The aggregate bandwidth of the source links (SVC leaves) cannot exceed the bandwidth allocated to the funnel link. A maximum of 255 links (leaf SVCs) can join the funnel link. Arbitration is performed between the sources to avoid overloading of the funnel link by the application running.
When the switch receives a setup message containing a leaf-initiated join information element, the switch searches for funnel SVCs with existing connections to the destination. The leaf-initiated join information element connection ID and the destination ATM address uniquely identify each funnel SVC.
If a funnel SVC to the same destination arrives with the same leaf-initiated join element connection ID, as one that is already present, the switch checks to see if the traffic parameters specified in the incoming setup message are the same as those in the funnel SVC. If the parameters are the same, then the leaf is joined to the funnel SVC, and the connection is acknowledged. If the traffic parameters are different, then the setup request is denied. If a funnel SVC to the specified destination is not available when an incoming setup message arrives, then a point-to-point SVC is set up to transmit the message.
To display multipoint-to-point funnel connections, use the following EXEC commands:
| Command | Task |
|---|---|
show atm status | Display the number of active funnels. |
show atm vc cast mp2p | Display the status of the multipoint-to-point messages on the specific interfaces. |
Use the show atm status command to display the number of active funnels, point-to-point and point-to-multipoint setup messages. An example of the show atm status command output follows:
Switch# show atm status
NUMBER OF INSTALLED CONNECTIONS: (P2P=Point to Point, P2MP=Point to MultiPoint, MP2P=Multipoint to Point)
Type PVCs SoftPVCs SVCs TVCs PVPs SoftPVPs SVPs Total
P2P 26 0 0 0 2 0 0 28
P2MP 1 0 0 0 0 0 0 1
MP2P 0 0 1 0 0 0 0 1
TOTAL INSTALLED CONNECTIONS = 30
PER-INTERFACE STATUS SUMMARY AT 13:34:48 UTC Thu Jan 29 1998:
Interface IF Admin Auto-Cfg ILMI Addr SSCOP Hello
Name Status Status Status Reg State State State
------------- -------- ------------ -------- ------------ --------- --------
ATM0/0/0 UP up done UpAndNormal Active 2way_in
ATM0/0/1 DOWN down waiting n/a Idle n/a
ATM0/0/2 UP up done UpAndNormal Active 2way_in
ATM0/0/3 UP up done UpAndNormal Active 2way_in
ATM0/0/3.55 UP up waiting WaitDevType Idle n/a
ATM0/0/3.60 UP up waiting WaitDevType Idle n/a
ATM0/0/3.65 UP up waiting WaitDevType Idle n/a
ATM0/1/0 UP up n/a UpAndNormal Active n/a
ATM0/1/1 UP up done UpAndNormal Active n/a
ATM0/1/2 DOWN shutdown waiting n/a Idle n/a
ATM0/1/3 DOWN down waiting n/a Idle n/a
Use the show atm vc cast mp2p command to display the status of the multipoint-to-point messages on the specific interfaces. An example of the show atm vc cast mp2p command output follows:
Switch# show atm vc cast mp2p
Interface VPI VCI Type X-Interface X-VPI X-VCI Encap Status
ATM0/1/0 0 40 SVC ATM0/1/1 0 35 UP
ATM0/1/1 0 36 UP
ATM0/1/1 0 35 SVC ATM0/1/0 0 40 UP
ATM0/1/1 0 36 SVC ATM0/1/0 0 40 UP
Posted: Tue Jun 22 13:59:32 PDT 1999
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