In-service software upgrade on cards of virtual partition of network element that includes directing traffic away from cards of virtual partition

• US 8,402,454 B2
• Filed: 09/22/2010
• Issued: 03/19/2013
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wang, Dawei, Gupta, Rajeev, Wen, Renhua
• Primary Examiner(s): Das, Chameli
• Application Number:
  US12/888,405
• Publication Number:
  US 20120072894A1
• Time in Patent Office: 909 Days
• Field of Search: None
• US Class Current: 717/172
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57
• CPC Class Codes: G06F 8/656 while running

Abstract

A method within network element, for directing traffic away from cards of first virtual partition, before changing software on cards of first virtual partition, until after cards of first virtual partition have session data, while network element services sessions. Redistribute sessions, serviced by cards of first virtual partition, to cards of second virtual partition. Each of virtual partitions has control card and line card. Direct traffic away from cards of first virtual partition, prior to taking line card of first virtual partition offline. After redistributing sessions, change software on line card of first virtual partition, while cards of second virtual partition service sessions, including redistributed sessions. After changing software, synchronize session data, for sessions serviced by cards of second virtual partition to cards of first virtual partition. Traffic is directed away from cards before changing software on line card, and until after synchronizing session data to cards of first partition.

Claims

1. A method performed within a network element, for directing traffic away from cards of a first virtual partition, before changing software on the cards of the first virtual partition, until after the cards of the first virtual partition have session data, and while the network element services sessions, the method comprising:

redistributing sessions, currently serviced by the cards of the first virtual partition of the network element, to cards of a second virtual partition of the network element, each of the first and second virtual partitions having at least one control card and at least one line card;

performing the directing the traffic away from the cards of the first virtual partition, prior to taking the at least one line card of the first virtual partition offline;

after the redistributing the sessions, from the cards of the first virtual partition to the cards of the second virtual partition, performing the changing the software on the at least one line card of the first virtual partition, while the cards of the second virtual partition service sessions, including the sessions redistributed from the cards of the first virtual partition; and

after the changing the software on the at least one line card of the first virtual partition, synchronizing session data, for sessions currently serviced by the cards of the second virtual partition, from the cards of the second virtual partition to the cards of the first virtual partition,

wherein the directing the traffic away from the cards of the first virtual partition is performed before the changing the software on the at least one line card of the first virtual partition, and continues until after the synchronizing the session data from the cards of the second virtual partition to the cards of the first virtual partition,

whereby speed of traffic movement away from the cards of the first virtual partition is increased by the directing of the traffic away from the first virtual partition prior to the taking of the at least one line card of the first virtual partition offline, and the traffic is directed away from the cards of the first virtual partition until after the cards of the first virtual partition have session data to handle the traffic.

2. The method of claim 1, wherein the directing the traffic away from the cards of the first virtual partition comprises influencing a routing protocol decision.

3. The method of claim 2, wherein the influencing the routing protocol decision comprises changing one or more routing protocol metrics to make a routing protocol metric corresponding to the cards of the first virtual partition inferior to a routing protocol metric corresponding to the cards of the second virtual partition.

4. The method of claim 1, wherein the directing the traffic away from the first virtual partition comprises actively notifying an external network that a network address of the at least one line card of the first virtual partition is withdrawn.

5. The method of claim 1, further comprising:

after the changing the software on the at least one line card of the first virtual partition, redistributing the sessions currently serviced by the cards of the second virtual partition, from the cards of the second virtual partition to the cards of the first virtual partition;

directing traffic away from the cards of the second virtual partition, prior to taking the at least one line card of the second virtual partition offline;

after the redistributing the sessions from the cards of the second virtual partition to the cards of the first virtual partition, changing software on the at least one line card of the second virtual partition and on the at least one control card of the second virtual partition, while the cards of the first virtual partition service sessions including the sessions redistributed from the cards of the second virtual partition,

after the changing the software on the at least one line card of the second virtual partition and on the at least one control card of the second virtual partition, synchronizing session data, for a portion of sessions currently serviced by the cards of the first virtual partition, from the cards of the first virtual partition to the cards of the second virtual partition,

wherein the directing the traffic away from the cards of the second virtual partition is performed prior to the changing the software on the at least one line card of the second virtual partition and on the at least one control card of the second virtual partition, and continues until after the synchronizing the session data, for the portion of the sessions, from the cards of the first virtual partition to the cards of the second virtual partition.

6. The method of claim 1, wherein the network element is configured to use a distributed control plane, wherein the at least one control card of the second virtual partition comprises a primary control card and one or more secondary control cards that receive distributed control plane process instances from the primary control card, and the method further comprises:

the primary control card of the second virtual partition, while servicing the sessions after the changing the software on the at least one line card of the first virtual partition, providing the distributed control plane process instances to only the one or more secondary control cards of the second virtual partition, and not to any secondary control cards within the first virtual partition.

7. The method of claim 1, wherein the servicing of the sessions with the cards of the second virtual partition, after the changing the software on the at least one line card of the first virtual partition, comprises the at least one control card of the second virtual partition communicating with line cards only in the second virtual partition, and not with line cards in the first virtual partition.

8. The method of claim 1, wherein the changing the software on the at least one line card of the first virtual partition comprises changing at least one of field-programmable gate array (FPGA) software, application-specific integrated circuit (ASIC) software, kernel software, and microcode.

9. The method of claim 1, further comprising receiving an in-service software upgrade (ISSU) command that specifies that the first virtual partition is to have the at least one control card of the first virtual partition and the at least one line card of the first virtual partition, and that specifies that the second virtual partition is to have the at least one control card of the second virtual partition and the at least one line card of the second virtual partition, and wherein the method is performed responsive to receipt of the ISSU command.

10. The method of claim 1, further comprising, after the changing the software on the at least one line card of the first virtual partition:

translating the session data that is synchronized from the not yet changed software of the at least one control card of the second virtual partition to the already changed software of the at least one control card of the first virtual partition; and

providing the translated session data from the at least one control card of the first virtual partition to the at least one line card of the first virtual partition,

whereby translation complexity is avoided by avoiding translating sessions from the not yet changed software of the at least one control card of the second virtual partition to the already changed software of the at least one line card of the first virtual partition.

11. A network element having a plurality of line cards, that is operable to direct traffic away from a first set of the plurality of line cards, before upgrading software on the first set of the plurality of line cards, until after the first set of the plurality of line cards have session data, and while the network element services sessions, the network element comprising:

a plurality of control cards coupled together;

the plurality of line cards coupled with the control cards and coupled together, wherein each of the plurality of line cards have line card software;

an interface to receive an in-service software upgrade (ISSU) command; and

an ISSU system that, responsive to the ISSU command, is operable to cause the network element to;

direct traffic away from the first set of the plurality of line cards, prior to taking the first set of the plurality of line cards offline;

upgrade the line card software on the first set of the plurality of line cards, after taking the first set of the plurality of line cards offline, and while a second set of the plurality of the line cards is online and operable to receive traffic associated with the sessions serviced by the network element;

bring the first set of the plurality of line cards online, after the line card software has been upgraded on the first set of the plurality of line cards,

wherein in directing the traffic away from the first set of the plurality of line cards, the network element is operable to direct the traffic away from the first set of the plurality of line cards, prior to upgrading the line card software on the first set of the plurality of line cards, and until after the session data for the sessions serviced by the network element is available to the first set of the plurality of line cards,

whereby speed of traffic movement away from the first set of the plurality of line cards is increased by the directing of the traffic away from the first set of the plurality of line cards, prior to taking the first set of the plurality of line cards offline, and the traffic is directed away from the first set of the plurality of line cards until after session data to handle the traffic is available to the first set of the plurality of line cards.

12. The network element of claim 11, wherein the network element is operable to direct the traffic away from the first set of the plurality of line cards by influencing a routing protocol decision.

13. The network element of claim 12, wherein the network element is operable to influence the routing protocol decision by changing one or more routing protocol metrics to make a routing protocol metric corresponding to the first set of the plurality of line cards inferior to a routing protocol metric corresponding to the second set of the plurality of line cards.

14. The network element of claim 11, wherein the network element is operable to direct the traffic away from the first set of the plurality of line cards by actively notifying an external network that one or more network addresses corresponding to the first set of the plurality of line cards are withdrawn.

15. The network element of claim 11, wherein the network element, responsive to the ISSU command, is further operable to:

direct traffic away from the second set of the plurality of line cards, after upgrading the software of the first set of the plurality of line cards, and prior to taking the second set of the plurality of line cards offline;

upgrade the line card software on the second set of the plurality of line cards and upgrade control card software on a second set of the plurality of control cards, after taking the second set of the plurality of line cards offline, and while the first set of the plurality of line cards is online and operable to receive traffic associated with the sessions serviced by the network element;

bring the second set of the plurality of line cards online, after the line card software has been upgraded on the second set of the plurality of line cards,

wherein the network element is operable to perform the directing of the traffic away from the second set of the plurality of line cards, prior to upgrading the line card software on the second set of the plurality of line cards, and until after session data for the sessions serviced by the network element is available at the second set of the plurality of control cards; and

direct traffic to both the first and second sets of the plurality of line cards, after the software has been upgraded on both the first and second sets of the plurality of line cards.

16. The network element of claim 11, wherein the first set of the plurality of line cards provides connections to all different external networks for which connections are provided by the second set of the plurality of line cards, and wherein the second set of the plurality of line cards provides connections to all different external networks for which connections are provided by the first set of the plurality of line cards.

17. The network element of claim 11, wherein the ISSU command associates the first set of the plurality of line cards as a group and associates the second set of the plurality of line cards as a group.

18. The network element of claim 11, wherein the upgrade of the line card software on the first set of the plurality of line cards comprises an upgrade of at least one of field-programmable gate array (FPGA) software, application-specific integrated circuit (ASIC) software, kernel software, and microcode.

19. The network element of claim 11, wherein the network element is operable to take the first set of the plurality of line cards offline after traffic to the first set of the plurality of line cards has stopped.

20. The network element of claim 11, wherein the network element is operable to perform the upgrade of the software on the first set of the plurality of line cards without stalling sessions that were previously serviced by the first set of the plurality of line cards.