Configuring the DCP

Context

The TLPs on DCPs are the executors in packet loss measurement. The TLPs count the number of sent and received packets in target flows, and DCPs collect statistics data from all TLPs and report statistics data to the MCP.

The measurement instance parameters of a DCP configured in this task must be the same as the parameters of the same measurement instance on the MCP; otherwise, the DCPs cannot send statistics data to the MCP.

Procedure

Run the system-view command to enter the system view.
Run the nqa ipfpm dcp command to enable the global DCP function and enter the IPFPM-DCP view.
Run the dcp id dcp-id command to set the DCP ID.
By default, a DCP has no ID. A DCP has a unique ID on the network. It is recommended that you configure the router ID of the device as the DCP ID.
(Optional) Run the authentication-mode hmac-sha256 key-id key-id [ cipher ] password command to configure the authentication mode and password on the DCP.
By default, no authentication mode or password is configured on a DCP.

The authentication modes and passwords on the MCP and DCPs must be the same so that the MCP receives the packets only from authenticated DCPs. This improves statistics data security and reliability.
Run the color-flag loss-measure { tos-bit tos-bit | flags-bit0 } command to configure the color bit used in network-level packet loss measurement.
By default, bit 6 in the ToS field is used as the color bit for network-level packet loss measurement. The default configuration is recommended.

All devices on a network must use the same color bit setting.

When both network-level and device-level packet loss measurements are enabled on a device, the color bits must be differentiated.

RFC2474 defines the ToS field in the IPv4 packet header as the Differentiated Service (DS) field. In the DS field, the leftmost 6 bits (bits 0-5) are the DS Code Point (DSCP). When the DS field is used to provide differentiated service, it is not recommended that you configure bits 3-5 as color bits because the measurement result may be inaccurate.
Run the mcp mcp-id [ port port-number ] [ vpn-instance vpn-instance-name | net-manager-vpn ] command to associate the MCP ID with all measurement instances on the DCP, and configure the UDP port number through which the DCP and MCP communicate with each other.
By default, no MCP ID is associated with the measurement instances on the DCP, and the DCP and MCP communicate with each other through UDP port 65030.
The DCP receives statistics data from TLPs, and sends the statistics data to the destination IP address, which is the MCP ID associated with the measurement instance. When receiving the packet carrying the measurement result from the DCP, the MCP compares the MCP ID in the packet with the MCP ID locally configured by the mcp id command.
- If the two MCP IDs are the same, the MCP accepts the packet, and then summarizes and calculates the statistics data.
- If the two MCP IDs are different, the MCP considers the packet invalid and discards it.
Configure measurement instances on the DCP.
The DCP collects statistics data based on measurement instances. Each measurement instance consists of the target flow, TLP, and measurement interval. To measure packet loss for a specified service flow, create a measurement instance.
1. Run the instance instance-id command to create a measurement instance and enter the IPFPM-DCP instance view.
  By default, no measurement instance exists on a DCP.
2. (Optional) Run the authentication-mode hmac-sha256 key-id key-id [ cipher ] password command to configure the authentication mode and password for the measurement instance.
  By default, no authentication mode or password is configured for a measurement instance.
  
  If no authentication mode or password is configured for a measurement instance, the authentication mode and password configured in the IPFPM-DCP view (step 4) are used for this instance. If the authentication mode and password are configured for a measurement instance, the configuration in this step is used.
3. Run the mcp mcp-id [ port port-number ] [ vpn-instance vpn-instance-name | net-manager-vpn ] command to associate the MCP ID with the measurement instance, and configure the UDP port number through which the DCP and MCP communicate with each other.
  By default, no MCP ID is associated with a measurement instance, and the DCP and MCP communicate with each other through UDP port 65030. If no MCP ID is associated with the measurement instance, the MCP ID specified in the IPFPM-DCP view (step 6) is used. If an MCP ID is associated with the measurement instance, the configuration in this step is used.
  The DCP receives statistics data from TLPs, and sends the statistics data to the destination IP address, which is the MCP ID associated with the measurement instance. When receiving the packet carrying the measurement result from the DCP, the MCP compares the MCP ID in the packet with the MCP ID locally configured by the mcp id command.
  - If the two MCP IDs are the same, the MCP accepts the packet, and then summarizes and calculates the statistics data.
  - If the two MCP IDs are different, the MCP considers the packet invalid and discards it.
4. Define a target flow in the measurement instance.
  A target flow is the objective in iPCA measurement, and can be defined by any combinations of source IP address, destination IP address, protocol type, DSCP value, source port number, and destination port number. Specifying more attributes can make the target flow accurate. Therefore, it is recommended that you specify more attributes to improve precision of measurement results.
  
  A target flow is transmitted in a certain direction. If a target flow is unidirectional, only a forward flow or a backward flow needs to be configured. If a target flow is bidirectional (the source and destination addresses of forward and backward flows mirror to each other), only a bidirectional symmetrical flow needs to be configured. The system then automatically generates two symmetrical unidirectional flows. If the source and destination addresses are not mirrored, two unidirectional flows need to be configured.
  
  A measurement instance can contain only one unidirectional flow or bidirectional flow (two unidirectional flows logically). Different measurement instances cannot contain the same target flow. That is, a target flow cannot belong to both instance A and instance B, and the forward flow and backward flow in the same measurement instance cannot be the same.
  - Define a unidirectional flow.
    - When the protocol of a target flow is TCP or UDP, run the following command:
      
      flow { forward | backward } { protocol { tcp | udp } { source-port src-port-number1 [ to src-port-number2 ] | destination-port dest-port-number1 [ to dest-port-number2 ] } ^* | dscp dscp-value | source src-ip-address [ src-mask-length ] | destination dest-ip-address [ dest-mask-length ] } ^*
    - When the protocol of a target flow is not TCP or UDP, run the following command:
      
      flow { forward | backward } { protocol protocol-number | dscp dscp-value | source src-ip-address [ src-mask-length ] | destination dest-ip-address [ dest-mask-length ] } ^*
  - Define a bidirectional symmetrical flow.
    - When the protocol of a target flow is TCP or UDP, run the following command:
      
      flow bidirectional { protocol { tcp | udp } { source-port src-port-number1 [ to src-port-number2 ] | destination-port dest-port-number1 [ to dest-port-number2 ] } ^* | dscp dscp-value | source src-ip-address [ src-mask-length ] | destination dest-ip-address [ dest-mask-length ] } ^*
    - When the protocol of a target flow is not TCP or UDP, run the following command:
      
      flow bidirectional { protocol protocol-number | dscp dscp-value | source src-ip-address [ src-mask-length ] | destination dest-ip-address [ dest-mask-length ] } ^*
  If the target flow entering a DCP has been fragmented, the device counts only the first fragment. Therefore, if a transit device on the network has fragmented the target flow, the measurement result may be inaccurate.
  
  When you define a bidirectional symmetrical flow, you must specify the source and destination IP addresses.
5. Run the interval interval command to set the measurement interval.
  By default, the measurement interval is 10 seconds.
  
  Before changing the measurement interval, disable packet loss measurement in the IPFPM-DCP instance view.
  
  The measurement interval of a measurement instance cannot be changed when the measurement instance is running. If the measurement interval of a running measurement instance is changed, the statistics reported by MCP may be inaccurate. To change the measurement interval, run the measure disable command in the IPFPM-MCP instance view to disable the measurement, and then run the measure enable command to enable the measurement.
6. (Optional) Run the description text command to configure the description of the measurement instance.
  By default, a measurement instance does not have a description, and the instance is identified by an ID in integer format. The description helps you understand the service monitored by the measurement instance and avoids misuse on the measurement instance. For example, if a measurement instance is configured to measure packet loss in the traffic from headquarters to branch 1, the description of the instance can be set to HeaderToBranch1.
7. Run the tlp tlp-id { in-point | out-point } { ingress | egress } command to configure the TLPs of the measurement instance and their roles.
  TLPs are the measurement points in the measurement instance. They collect data and generate statistics. By default, no TLP is configured.
  
  in-point indicates that the device colors the target flow; out-point indicates that the device removes the color flag from the target flow. ingress indicates that the target flow arrives at the TLP; egress indicates that the target flow leaves the TLP.
Run the quit command to return to the IPFPM-DCP view.
Run the quit command to return to the system view.
Bind interfaces to TLPs.
1. Run the interface interface-type interface-number command to enter the view of the interface to be bound to a TLP.
  
  The physical Ethernet interfaces and Eth-Trunks can be bound to TLPs.
2. Run the ipfpm tlp tlp-id command to bind the interface to a TLP.
  
  By default, an interface is not bound to a TLP.
  
  One interface can only be bound to one TLP, and one TLP can only be bound to one interface.
Run the quit command to return to the system view.
Enable packet loss measurement for an instance.
1. Run the nqa ipfpm dcp command to enter the IPFPM-DCP view.
2. Run the instance instance-id command to enter the IPFPM-DCP instance view.
3. Enable packet loss measurement for an instance.
  - If you have known that the network performance is low and want to locate the problematic network node, run the loss-measure enable [ time-range time-range ] command to start packet loss measurement within a specified time range.
    
    By default, packet loss measurement based on time range is disabled.
  - If you are unaware of network performance degrading and want to continuously monitor packet loss on the network, run the loss-measure enable continual command to enable continual packet loss measurement.
    
    By default, continual packet loss measurement is disabled.