Foundry Networks FESX - Policy and Filter Precedence Q O S

Policies and Filters
December 2005 © Foundry Networks, Inc. C - 3
policies and filters, the default action changes once you configure a policy or filter, regardless of the policy or
filter’s contents.
Policy and Filter Precedence
QoS
You can apply QoS policies to individual ports, VLANs, static MAC address, Layer 4 sessions, and AppleTalk
sockets. If a port is a member of two or more of these items and has different priorities, the priorities are merged.
However, the resulting priority is never lower than the highest priority.
Precedence Among Filters on Different Layers
Generally, the Foundry device applies only the type of filter that applies to the traffic. For example, if a packet is a
Layer 2 switched packet, then the device evaluates the packet against the port’s MAC filters. If a packet is a routed
IP packet, the device evaluates the packet against the port’s IP access policies.
Foundry recommends that you do not use filters at different layers on the same port. For example, do not use
MAC filters and IP access policies on the same port.
NOTE: You cannot use Layer 2 filters to filter for Layer 4 information. To filter for Layer 4 information, use IP
access policies (filters).
Table C.3: Default Policy and Filter Actions
Policy or Filter Type Default action when no policies
or filters are configured
Default action after a policy or
filter is configured
QoS policy Queue all packets in normal or 0
priority queue
Queue all packets in normal or 0
priority queue unless explicitly
configured for a higher queue
Address-lock filter Permit (forward) all packets Permit only those packets whose
source MAC addresses have been
learned on the port; drop all others
Route filters
• RIP neighbor filters
• BGP4 address filters
• BGP4 AS-path filters
• BGP4 community filters
Permit (learn and advertise) all
routes or services
Deny (do not learn or advertise) all
routes or services
Route filters
• RIP route filters
Permit (learn and advertise) all
routes or services
Permit (learn and advertise) all
routes or services
Route redistribution filter
•RIP
• OSPF
•BGP4
Redistribute all routes if
redistribution is enabled.
Once redistribution is enabled,
redistribute routes of the specified
type unless explicitly denied by filter
Note: For RIP and OSPF, you must
explicitly enable redistribution.
Redistribution is enabled by default
in BGP4.