Route Maps; Implementation Information; Logging Of Acl Processes - Dell S4048–ON Configuration Manual

Route Maps

Although route maps are similar to ACLs and prefix lists in that they consist of a series of commands that contain a matching criterion and
an action, route maps can modify parameters in matching packets.

Implementation Information

ACLs and prefix lists can only drop or forward the packet or traffic. Route maps process routes for route redistribution. For example, a route
map can be called to filter only specific routes and to add a metric.
Route maps also have an "implicit deny." Unlike ACLs and prefix lists; however, where the packet or traffic is dropped, in route maps, if a
route does not match any of the route map conditions, the route is not redistributed.
The implementation of route maps allows route maps with the no match or no set commands. When there is no match command, all traffic
matches the route map and the set command applies.

Logging of ACL Processes

This functionality is supported on the platform.
To assist in the administration and management of traffic that traverses the device after being validated by the configured ACLs, you can
enable the generation of logs for access control list (ACL) processes. Although you can configure ACLs with the required permit or deny
filters to provide access to the incoming packet or disallow access to a particular user, it is also necessary to monitor and examine the
traffic that passes through the device. To evaluate network traffic that is subjected to ACLs, configure the logs to be triggered for ACL
operations. This functionality is primarily needed for network supervision and maintenance activities of the handled subscriber traffic.
When ACL logging is configured, and a frame reaches an ACL-enabled interface and matches the ACL, a log is generated to indicate that
the ACL entry matched the packet.
When you enable ACL log messages, at times, depending on the volume of traffic, it is possible that a large number of logs might be
generated that can impact the system performance and efficiency. To avoid an overload of ACL logs from being recorded, you can
configure the rate-limiting functionality. Specify the interval or frequency at which ACL logs must be triggered and also the threshold or
limit for the maximum number of logs to be generated. If you do not specify the frequency at which ACL logs must be generated, a default
interval of 5 minutes is used. Similarly, if you do not specify the threshold for ACL logs, a default threshold of 10 is used, where this value
refers to the number of packets that are matched against an ACL .
A Layer 2 or Layer 3 ACL contains a set of defined rules that are saved as flow processor (FP) entries. When you enable ACL logging for a
particular ACL rule, a set of specific ACL rules translate to a set of FP entries. You can enable logging separately for each of these FP
entries, which relate to each of the ACL entries configured in an ACL. Dell Networking OS saves a table that maps each ACL entry that
matches the ACL name on the received packet, sequence number of the rule, and the interface index in the database. When the
configured maximum threshold has exceeded, log generation stops. When the interval at which ACL logs are configured to be recorded
expires, a fresh interval timer starts and the packet count for that new interval commences from zero. If ACL logging was stopped
previously because the configured threshold has exceeded, it is reenabled for this new interval.
The ACL application sends the ACL logging configuration information and other details, such as the action, sequence number, and the ACL
parameters that pertain to that ACL entry. The ACL service collects the ACL log and records the following attributes per log message.
• For non-IP packets, the ACL name, sequence number, ACL action (permit or deny), source and destination MAC addresses, EtherType,
and ingress interface are the logged attributes.
• For IP Packets, the ACL name, sequence number, ACL action (permit or deny), source and destination MAC addresses, source and
destination IP addresses, and the transport layer protocol used are the logged attributes.
Access Control Lists (ACLs) 135