Enhancing transmission reliability of monitored data

• US 20080170501A1
• Filed: 01/17/2007
• Published: 07/17/2008
• Est. Priority Date: 01/17/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ramaiah, Anantha, Patel, Alpesh, Joshi, Praveen, Appala, Syam Sundar
• Granted Patent: US 7,593,331 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 47/19 at layers above the network layer network arrangements for networked applications for scheduling or organising the servicing of application requests H04L67/60
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/28 in relation to timing considerations
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

In one embodiment, an apparatus comprises logic encoded in one or more tangible media for enhancing transmission reliability of monitored data. The logic is operable to receive a plurality of segments for transmission over a TCP connection to a network node, where the TCP connection is associated with a transmit queue and a retransmit queue. The logic is also operable to detect a transmission anomaly on the TCP connection to the network node, and in response to detecting the transmission anomaly, is operable to perform any one of: store segments into a persistent buffer prior to transferring the segments into the transmit queue; copy segments from the retransmit queue into the persistent buffer, where the segments have been transmitted but not yet acknowledged by the network node; and copy segments from the transmit queue into the persistent buffer, where the segments have not yet been transmitted to the network node.

Claims

1. An apparatus comprising:

one or more processors; and

logic encoded in one or more tangible media for execution and when executed operable to;

receive a plurality of segments for transmission over a Transmission Control Protocol (TCP) connection to a network node, wherein the TCP connection when established is associated with a transmit queue and a retransmit queue;

detect a transmission anomaly on the TCP connection to the network node; and

in response to detecting the transmission anomaly, perform any one of;

prior to transferring first one or more segments of the plurality of segments into the transmit queue, store the first one or more segments into a persistent buffer;

copy second one or more segments of the plurality of segments from the retransmit queue into the persistent buffer, wherein the second one or more segments have been transmitted to, but have not yet been acknowledged by, the network node; and

copy third one or more segments of the plurality of segments from the transmit queue into the persistent buffer, wherein the third one or more segments have not yet been transmitted to the network node.

2. The apparatus of claim 1, further comprising logic which, when executed, is operable to:

determine that the transmission anomaly on the TCP connection has ceased to exist; and

transfer the first one or more segments from the persistent buffer into the transmit queue for transmission to the network node.

3. The apparatus of claim 1, wherein the logic that is operable to detect the transmission anomaly further comprises logic which, when executed, is operable to determine that one or more metrics exceed certain thresholds that indicate transmission delays over the TCP connection to the network node.

4. The apparatus of claim 3, wherein the one or more metrics include any one of:

average request-response times over the TCP connection;

round-trip latency over the TCP connection;

number of retransmissions over the TCP connection; and

number of not acknowledged segments transmitted over the TCP connection.

5. The apparatus of claim 1, wherein the logic that is operable to detect the transmission anomaly further comprises logic which, when executed, is operable to determine that a TCP segment received from the network node includes a header in which a window size field is set to zero.

6. The apparatus of claim 1, wherein:

the logic that is operable to detect the transmission anomaly further comprises logic which, when executed, is operable to determine that a TCP segment received from the network node includes a header in which a RST control flag is set; and

the apparatus further comprises logic which, when executed, is operable to;

in response to determining that the RST control flag in the header of the received TCP segment is set, establish a new TCP connection to the network node, wherein the new TCP connection is associated with a new transmit queue and a new retransmit queue; and

transfer the second one or more segments and the third one or more segments from the persistent buffer into the new transmit queue.

7. The apparatus of claim 1, wherein the logic that is operable to copy the second one or more segments and the third one or more segments into the persistent buffer further comprises logic which, when executed, is operable to invoke a TCP socket option call for the TCP connection, wherein the TCP socket option call causes the second one or more segments and the third one or more segments to be copied into the persistent buffer.

8. The apparatus of claim 1, further comprising one or more non-volatile storage media that are operable to store the persistent buffer.

9. The apparatus of claim 1, further comprising:

a first network interface that is operable to communicatively connect to a packet-switched network;

a second network interface that is operable to transmit the plurality of segments to the network node, wherein the network node is operable to process monitored data;

and

logic which when executed is operable to;

at the first network interface, capture a packet flow that is exchanged between two nodes that are communicatively connected over the packet-switched network;

copy a plurality of packets from the packet flow, wherein the plurality of packets represent the monitored data;

based on the plurality of packets, generate a plurality of framed messages that are formatted according to a particular protocol; and

generate the plurality of segments, wherein the plurality of framed messages are included in the payload portions of the plurality of segments.

10. The apparatus of claim 9, wherein the logic that is operable to capture the packet flow further comprises logic which, when executed, is operable to determine the plurality of packets by filtering the packet flow according to one or more criteria.

11. An apparatus comprising:

means for receiving a plurality of segments for transmission over a Transmission Control Protocol (TCP) connection to a network node, wherein the TCP connection when established is associated with a transmit queue and a retransmit queue;

means for detecting a transmission anomaly on the TCP connection to the network node; and

any one of;

means for storing first one or more segments of the plurality of segments into a persistent buffer when the transmission anomaly is detected, wherein the first one or more segments are stored in the persistent buffer prior to being transferred into the transmit queue;

means for copying second one or more segments of the plurality of segments from the retransmit queue into the persistent buffer when the transmission anomaly is detected, wherein the second one or more segments are copied into the persistent buffer after being transmitted to, but before being acknowledged by, the network node; and

means for copying third one or more segments of the plurality of segments from the transmit queue into the persistent buffer when the transmission anomaly is detected, wherein the third one or more segments are copied into the persistent buffer prior to being transmitted to the network node.

12. The apparatus of claim 11, further comprising:

means for determining that the transmission anomaly on the TCP connection has ceased to exist; and

means for transferring the first one or more segments from the persistent buffer into the transmit queue for transmission to the network node.

13. The apparatus of claim 11, wherein the means for detecting the transmission anomaly further comprise means for determining that one or more metrics exceed certain thresholds that indicate transmission delays over the TCP connection to the network node.

14. The apparatus of claim 13, wherein the one or more metrics include any one of:

average request-response times over the TCP connection;

round-trip latency over the TCP connection;

number of retransmissions over the TCP connection; and

number of not acknowledged segments transmitted over the TCP connection.

15. The apparatus of claim 11, wherein the means for detecting the transmission anomaly further comprise means for determining that a TCP segment received from the network node includes a header in which a window size field is set to zero.

16. The apparatus of claim 11, wherein:

the means for detecting the transmission anomaly further comprise means for determining that a TCP segment received from the network node includes a header in which a RST control flag is set; and

the apparatus further comprises;

means for establishing a new TCP connection to the network node in response to determining that the RST control flag in the header of the received TCP segment is set, wherein the new TCP connection is associated with a new transmit queue and a new retransmit queue; and

means for transferring the second one or more segments and the third one or more segments from the persistent buffer into the new transmit queue.

17. The apparatus of claim 11, wherein the means for copying the second one or more segments and the third one or more segments into the persistent buffer further comprise means for invoking a TCP socket option call for the TCP connection, wherein the TCP socket option call causes the second one or more segments and the third one or more segments to be copied into the persistent buffer.

18. The apparatus of claim 11, further comprising one or more non-volatile storage media that are operable to store the persistent buffer.

19. The apparatus of claim 11, further comprising:

a first network interface that is operable to communicatively connect to a packet-switched network;

a second network interface that is operable to transmit the plurality of segments to the network node, wherein the network node is operable to process monitored data;

means for capturing, at the first network interface, a packet flow that is exchanged between two nodes that are communicatively connected over the packet-switched network;

means for copying a plurality of packets from the packet flow, wherein the plurality of packets represent the monitored data;

means for generating, based on the plurality of packets, a plurality of framed messages that are formatted according to a particular protocol; and

means for generating the plurality of segments, wherein the plurality of framed messages are included in the payload portions of the plurality of segments.

20. The apparatus of claim 19, wherein the means for capturing the packet flow further comprise means for determining the plurality of packets by filtering the packet flow according to one or more criteria.

21. Logic encoded in one or more tangible media for execution and when executed operable to:

receive a plurality of segments for transmission over a Transmission Control Protocol (TCP) connection to a network node, wherein the TCP connection when established is associated with a transmit queue and a retransmit queue;

detect a transmission anomaly on the TCP connection to the network node; and

in response to detecting the transmission anomaly, perform any one of;

prior to transferring first one or more segments of the plurality of segments into the transmit queue, store the first one or more segments into a persistent buffer;

copy second one or more segments of the plurality of segments from the retransmit queue into the persistent buffer, wherein the second one or more segments have been transmitted to, but have not yet been acknowledged by, the network node; and

copy third one or more segments of the plurality of segments from the transmit queue into the persistent buffer, wherein the third one or more segments have not yet been transmitted to the network node.

22. A system comprising:

a monitoring node operable to process monitored data; and

an apparatus comprising;

a first network interface that is operable to communicatively connect to a packet-switched network;

a second network interface that is operable to communicatively connect to the monitoring node; and

logic encoded in one or more tangible media for execution and when executed operable to;

at the first network interface, capture a packet flow that is exchanged between two nodes that are communicatively connected over the packet-switched network;

copy a plurality of packets from the packet flow, wherein the plurality of packets represent the monitored data;

based on the plurality of packets, generate a plurality of framed messages that are formatted according to a particular protocol;

generate a plurality of segments, wherein the plurality of framed messages are included in the payload portions of the plurality of segments, wherein the plurality of segments are to be sent over a Transmission Control Protocol (TCP) connection to the monitoring node, wherein the TCP connection is associated with a transmit queue and a retransmit queue;

detect a transmission anomaly on the TCP connection to the monitoring node; and

in response to detecting the transmission anomaly, perform any one of;

prior to transferring first one or more segments of the plurality of segments into the transmit queue, store the first one or more segments into a persistent buffer;

copy second one or more segments of the plurality of segments from the retransmit queue into the persistent buffer, wherein the second one or more segments have been transmitted to, but have not yet been acknowledged by, the monitoring node; and

copy third one or more segments of the plurality of segments from the transmit queue into the persistent buffer, wherein the third one or more segments have not yet been transmitted to the monitoring node.