Cisco Cisco MGX-FRSM-HS2 B Serial Frame Service Module Libro blanco
Deployment Guide
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Figure 25. Creating a SPAN Session from NAM Traffic Analyzer
Using VACL as a Data Source Within NAM
Why would one use or not use VACLs compared to SPAN and NetFlow?
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With SPAN, it is easy to create the sessions with full monitoring capability using the NAM Traffic Analyzer.
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VACLs allow SPAN-like capability to WAN interfaces or when SPAN sessions are limited and run out. They
allow prefiltering of interesting traffic, specified subnets, or simply when traffic is too large. In addition, VACLs
can be implemented to direct traffic to multiple Cisco NAMs.
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NetFlow provides comprehensive statistics and doesn’t rely on SPAN or VACLs. It is also useful in collecting
data from the Cisco Catalyst 6500 Series Multilayer Switch Feature Card or remote devices such as routers.
Table 2 provides a summary of possible data sources for the Cisco NAM, including benefits and limitations.
VACLs provide an alternative to using SPAN for similar purposes. The NAM Traffic Analyzer will use VACLs to
capture or “filter” selected VLANs or (on Cisco IOS Software) WAN traffic to the NAM port or ports.
Note:
In Cisco IOS Software Release 12.1(13)E or later, VACLs can also be applied to WAN interfaces. VACLs
attached to WAN interfaces support only standard and extended Cisco IOS IP ACLs (not Internetwork Packet
Exchange [IPX] protocol or MAC). VACLs can only be applied to packet-over-SONET (POS), ATM, and serial WAN
interfaces. The VACL data analysis capability is not supported for the Cisco first-generation NAM.
The following examples illustrate the steps required to configure a VACL for a switch running native Cisco IOS
Software Release 12.1(13)E1 or later.
Configuring VACL on a WAN Interface
Cat6509#conf t
Enter configuration commands, one per line. End with CNTL/Z.
6509(config)#access-list 100 permit ip any any
6509(config)#vlan access-map wan 100
6509(config-access-map)#match ip address 100
6509(config-access-map)#action forward capture
6509(config-access-map)#exit
6509(config)#vlan filter wan interface ATM6/0/0.1
6509(config)#analysis module 3 data-port 1 capture allowed-vlan 1-4094
6509(config)#analysis module 3 data-port 1 capture
6509(config)#exit