Cisco Catalyst 4500 Series, Software Configuration Manual

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Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
Chapter 45 Configuring AVC with DNS-AS
Configuring AVC with DNS-AS
L4—IANA layer 4 well-known port number (IANA_L4_STANDARD, ID: 3)
L7—Cisco global application ID (CISCO_L7_GLOBAL, ID: 13)
CU—Custom protocol, (NBAR_CUSTOM, ID: 6). For custom applications, the DNS-AS client
automatically uses this engine ID.
– Selector ID—Uniquely identifies the application or classification.
For standard applications, the application tag information is derived from these sources, in the given
order of precedence:
1. TXT response (
app-id
:
)
2.
The NBAR definition for standard applications (if the TXT response does not carry a value)
For custom applications, the following applies to application tag information:
1.
It is derived only from the TXT response (
app-id :
)
2. For the engine ID, the DNS-AS client automatically uses CU—Custom protocol,
(NBAR_CUSTOM, ID: 6).
3.
For the selector ID, the DNS-AS client allots a custom selector ID. A maximum of 120 custom
applications are supported - out of which 110 are available to the DNS-AS client. Starting with
selector ID value 243, IDs are assigned in descending order. When there are no remaining IDs
to assign, the entry is not saved in the binding table.
• Description—This information is derived from the NBAR definition for standard applications. For
custom applications, the DNS-AS client uses: User Defined Protocol <app-name>
.
option application-attributes
Enables the collector to map the application names (from the option application-table ) to their
attributes. Attributes are statically assigned to each protocol or application, and are not dependent on
traffic.
For standard applicatons—
•
Application Tag—Guidelines that apply this field as part of the option application-table template
apply here as well.
• Category—Groups applications based on the first level of categorization for each protocol as the
match criteria. Similar applications are grouped together under one category. For example, the email
category contains all email applications such as, Internet Mail Access Protocol (IMAP), Simple
Mail Transfer Protocol (SMTP), Lotus Notes, and so on.
•
Sub-category—Groups applications based on the second level of categorization for each protocol as
the match criteria. For example, clearcase, dbase, rda, mysql and other database applications are
grouped under the database group.
• Application Group—Groups the same networking applications together. For instance,
Example-Messenger, Example-VoIP-messenger, and Example-VoIP-over-SIP are grouped together
under the example-messenger-group
•
Peer-to-peer (p2p)—Groups protocols based on whether or not they use p2p technology.
• Tunnel—Groups protocols based on whether or not a protocol tunnels the traffic of other protocols.
Protocols for which the NBAR does not provide any value are categorized under the unassigned
tunnel group. For example, Layer 2 Tunneling Protocols (L2TP).
•
Encryption—Groups applications based on the encrypted and nonencrypted status of the
applications. Protocols for which the NBAR does not provide any value are categorized under the
unassigned encrypted group.