Now for those customer who have multicast traffic enabled in their network, they can use NetFlow Analyzer and view the stats. IP Multicasting allows a host to send packets to a specific group of hosts. These hosts are called group members. In a multicast environment, packets delivered to group members are identified by a single multicast group address. A group of hosts consists of both senders and receivers. Any host, regardless of whether it is a member of a group, can send to a group. However, only the members of a group receive the message. NetFlow Analyzer displays IP Multicasting reports based on volume, speed, utilization and packets.
Some environment’s where Multicasting can be used are:
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Video Streaming
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Video Conferencing
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Online Radio
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In some finance sector for application like Stock tickers
Enabling Multicast routing in Cisco routers:
Following are the command to be enabled on Cisco Routers:
(config)ip multicast-routing
(config)ip multicast netflow output-counters
(config)ip multicast netflow rpf-failure
(config)interface fastethernet 0/0
(config-if)ip multicast netflow egress
PIM Configuration and rendezvous point address
(config-if)# ip pim sparse-mode
Note: Verify this command by using debug Step 1 in debugging.
(config)# ip pim rp-address 1.1.1.1
Note: Here, 1.1.1.1 is the meeting point address and can also be given as Auto-Rp
(config-if)# ip igmp join-group 239.0.0.0
Note: The Group addr is identified by using step 2 in debugging
Monitoring in NetFlow Analyzer
The IP Mulitcating can be view using the Flexible NetFlow by including the multicasting fields in exports. Given below is an example to export the flows.
Configuring FLOW EXPORTER:
cisco_281(config)#flow exporter FNFexp
cisco_281(config-flow-exporter)#destination 192.168.116.80
cisco_281(config-flow-exporter)#source fastEthernet 0/0
cisco_281(config-flow-exporter)#transport udp 9996
cisco_281(config-flow-exporter)#version 9
Configuring FLOW RECORD:
cisco_281(config)#flow record FNFREC
cisco_281(config-flow-record)#match routing is-multicast
cisco_281(config-flow-record)#match ipv4 protocol
cisco_281(config-flow-record)#match ipv4 source address
cisco_281(config-flow-record)#match ipv4 destination address
cisco_281(config-flow-record)#match transport source-port
cisco_281(config-flow-record)#match transport destination-port
cisco_281(config-flow-record)#collect routing multicast replication-factor
cisco_281(config-flow-record)#collect routing forwarding-status
cisco_281(config-flow-record)#collect ipv4 dscp
cisco_281(config-flow-record)#collect ipv4 ttl
cisco_281(config-flow-record)#collect ipv4 source mask
cisco_281(config-flow-record)#collect ipv4 destination mask
cisco_281(config-flow-record)#collect interface input
cisco_281(config-flow-record)#collect interface output
cisco_281(config-flow-record)#collect counter bytes
cisco_281(config-flow-record)#collect counter packets
cisco_281(config-flow-record)#collect counter bytes replicated
cisco_281(config-flow-record)#collect counter packets replicated
cisco_281(config-flow-record)#collect timestamp sys-uptime first
cisco_281(config-flow-record)#collect timestamp sys-uptime last
Flow records for IP Multicast routing
cisco_281(config-flow-record)#match routing is-multicast
cisco_281(config-flow-record)#collect routing multicast replication-factor
cisco_281(config-flow-record)#collect counter bytes replicated
cisco_281(config-flow-record)#collect counter packets replicated
The flow record and exporter now has to be associated with a flow monitor.
FLOW MONITOR:
cisco_281(config)#flow monitor FNFMON
cisco_281(config-flow-monitor)#exporter FNFEXP
cisco_281(config-flow-monitor)#record FNFREC
cisco_281(config-flow-monitor)#cache timeout active 1
cisco_281(config-flow-monitor)#cache timeout inactive 15
The flow monitor then has to be associated with each and every L3 interface of the router. The ‘input’ variable sets the flow collection for ingress traffic.
ASSOCIATING TO INTERFACE:
cisco_281(config)#int FastEthernet 0/0
cisco_281(config-if)#ip flow monitor FNFMON input
cisco_281(config)#int FastEthernet 0/1
cisco_281(config-if)#ip flow monitor FNFMON input
Once the configuration is done and saved, flows will be exported to the server where NetFlow Analyzer is installed. NetFlow Analyzer is based on automatic discovery and so the NetFlow exporting devices are automatically discovered and reports are generated within seconds of receiving the flows
To view the multicast traffic navigate to Devices drill down to the interfaces click on multicast tab.
The Graph will be shown as below:
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Arun Karthik Asokan
NetFlow Analyzer Technical Team
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