Communication device ingress information management system and method
View Patent ↗The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer. The classification filter counter value is incremented when the information is processed out of the buffer.
1. An ingress filtering method comprising:
associating each packet of a plurality of packets received at all of a plurality of ports of a network communication device with one of a plurality of classification types based on information in the packet;
writing each packet to a corresponding one of a plurality of storage buffer segments based on the associated classification type, wherein each of the plurality of classification types corresponds to one of the plurality of storage buffer segments;
decrementing, for each associated packet written to a storage buffer segment, a counter for the storage buffer segment; and
discarding associated packets received at the network communication device if the counter for the storage buffer segment corresponding to the classification type is at a predetermined limit.
2. The ingress filtering method of claim 1 further comprising:
incrementing the counter for the storage buffer segment when one of the associated packets written to the storage buffer segment is processed.
3. The ingress filtering method of claim 1 wherein the counter for each storage buffer segment has an initial value that corresponds to a predetermined maximum amount of storage buffer space allocated to the classification type corresponding to the segment.
4. The ingress filtering method of claim 1 wherein the predetermined limit is zero.
5. The ingress filtering method of claim 1 further comprising:
counting, for each classification, a number of discarded associated packets to detect a denial of service attack.
6. A communication system comprising:
an ingress classifier operable to associate packets received at all of a plurality of ports of a network communication device with one of a plurality of classification types based on information in the packets;
an ingress classification filter communicatively coupled to the ingress classifier and operable to discard associated packets of a particular classification type if a counter associated with a storage buffer segment corresponding to the particular classification type is at a predetermined limit;
a storage buffer including a plurality of segments, each segment corresponding to a different one of the plurality of classification types and having an associated counter, for temporarily storing non-discarded associated packets from the classification filter, wherein the counter for each segment is decremented upon storing an associated packet and incremented when an associated packet is processed by a processor coupled to the storage buffer.
7. The communication system of claim 6 wherein said ingress classification filter prevents packets associated with a first classification type from taking storage space allocated to a second classification type.
8. The communication system of claim 6 wherein the predetermined limit is zero.
9. The communication system of claim 8 wherein said ingress classification filter identifies potential denial of service attempts.
10. The communication system of claim 9 wherein said ingress classification filter provides a notification of a potential denial of service to a remote system.
11. The ingress filtering method according to claim 1 , wherein decrementing the counter for the storage buffer segment further comprises decrementing the counter for the storage buffer segment irrespective of the port through which the associated packet was received.
12. The communication system according to claim 6 , wherein the counter for each segmented is decremented upon storing an associated packet irrespective of the port through which the associated packet was received.