In-Service Software Upgrade of Control and Line Cards of Network Element

A network element, that is operable to upgrade software on both control and line cards thereof, while the network element services sessions, the network element comprising:

• a plurality of control cards coupled together, wherein each of the control cards have control card software;
• a plurality of line cards coupled with the control cards and coupled together, wherein each of the line cards have line card software;
• an interface to receive an in-service software upgrade (ISSU) command;
• an ISSU system that, responsive to the ISSU command, is operable to cause the network element to:
• take a first set of one or more of the line cards offline;
• upgrade the line card software on the first set of the line cards, after taking the first set of the line cards offline, and while a second set of one or more 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 line cards online, and take the second set of the line cards offline, after the line card software has been upgraded on the first set of the line cards;
• upgrade the line card software on the second set of the line cards and upgrade the control card software on a second set of one or more of the control cards, after taking the second set of the line cards offline, and while the first set of the line cards is online and operable to receive traffic associated with the sessions serviced by the network element;
• bring the second set of the line cards online, after the line card software has been upgraded on the second set of the line cards;
• and
• receive traffic associated with the sessions serviced by the network element at both the first and second sets of the line cards, after upgrading the software on the first and second sets of the line cards and the second set of the control cards,
• whereby the software may be upgraded on both the control and line cards of the network element, while the network element services the sessions, so that service interruption due to the upgrading of the software reduced.

A network element, that is operable to upgrade software on both control and line cards thereof, while the network element services sessions, the network element comprising:

• a plurality of control cards coupled together;
• a plurality of line cards coupled with the control cards and coupled together;
• a first control card of the plurality having a first in-service software upgrade (ISSU) manager module (ISSU-MM), a virtual partition creation/elimination module (VPM), and a first session distribution module (SDM);
• and
• a second control card of the plurality having a second ISSU-MM and a second SDM,
• the first ISSU-MM operable to receive an ISSU command,
• the VPM operable, when instructed by the first ISSU-MM, to virtually partition the control cards and the line cards into a virtual partition A and a virtual partition B, with each of the virtual partitions having a plurality of cards, the virtual partition A having the first control card and at least one line card, and the virtual partition B having the second control card and at least one line card,
• the first SDM operable, when instructed by the first ISSU-MM, to redistribute sessions currently serviced by the cards of the virtual partition A to the cards of the virtual partition B, and
• the first ISSU-MM operable, after the first SDM redistributes the sessions, to initiate an ISSU of software on, at least, the at least one line card of the virtual partition A, while the cards of the virtual partition B service sessions including the sessions redistributed from the cards of the virtual partition A;
• and
• the second SDM operable, after the ISSU on the at least one line card of the virtual partition A, and when instructed by the second ISSU-MM, to redistribute sessions currently serviced by the cards of the virtual partition B to the cards of the virtual partition A;
• the second ISSU-MM operable, after the second SDM redistributes the sessions, to initiate an ISSU of software on, at least, the second control card and the at least one line card of the virtual partition B, while the cards of the virtual partition A service sessions including the sessions redistributed from the cards of the virtual partition B;
• the VPM operable, after the ISSU on the second control card and the at least one line card of the virtual partition B, when instructed by the first ISSU-MM to eliminate the virtually partitions;
• and
• the first SDM operable, when instructed by the first ISSU-MM, to redistribute a portion of the sessions currently serviced by the cards of the virtual partition A to the cards of the virtual partition B,
• whereby the software may be upgraded on both the control and line cards of the network element, while the network element services the sessions, so that service interruption due to the upgrading of the software reduced.