BGP hitless upgrade approaches

A network routing apparatus, comprising:

• an active route processor;
• a standby route processor that is coupled to the active route processor in a redundant arrangement;
• a computer-readable medium that is accessible to the active route processor and the standby route processor, and comprising one or more sequences of instructions which, when executed by the route processors, cause the route processors to perform the steps of:
• receiving a new version of Border Gateway Protocol (BGP) software on a standby route processor that is coupled to an active route processor in a redundant arrangement;
• transferring, from the active route processor to the standby route processor, one or more transport protocol connections that are associated with one or more active BGP sessions of the active route processor;
• transferring, from the active route processor to the standby route processor, BGP session information representing the active BGP sessions;
• progressively shutting down an active BGP process of the active route processor;
• and
• switching control of BGP data processing to the standby route processor.

A network routing apparatus, comprising:

• an active route processor;
• a standby route processor that is coupled to the active route processor in a redundant arrangement;
• means for receiving a new version of Border Gateway Protocol (BGP) software on a standby route processor that is coupled to an active route processor in a redundant arrangement;
• means for transferring, from the active route processor to the standby route processor, one or more transport protocol connections that are associated with one or more active BGP sessions of the active route processor;
• means for transferring, from the active route processor to the standby route processor, BGP session information representing the active BGP sessions;
• means for progressively shutting down an active BGP process of the active route processor;
• and
• means for switching control of BGP data processing to the standby route processor.

A computer-readable medium carrying one or more sequences of instructions for upgrading network protocol software, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps of:

• receiving a new version of Border Gateway Protocol (BGP) software on a standby route processor that is coupled to an active route processor in a redundant arrangement;
• transferring, from the active route processor to the standby route processor, one or more transport protocol connections that are associated with one or more active BGP sessions of the active route processor;
• transferring, from the active route processor to the standby route processor, BGP session information representing the active BGP sessions;
• progressively shutting down an active BGP process of the active route processor;
• and
• switching control of BGP data processing to the standby route processor.

A method, comprising:

• receiving a new version of Border Gateway Protocol (BGP) software on a standby route processor that is coupled to an active route processor in a redundant arrangement;
• transferring, from the active route processor to the standby route processor, one or more transport protocol connections that are associated with one or more active BGP sessions of the active route processor;
• transferring, from the active route processor to the standby route processor, BGP session information representing the active BGP sessions;
• progressively shutting down an active BGP process of the active route processor;
• and
• switching control of BGP data processing to the standby route processor;
• wherein the route processors are placed in a stateful switchover mode of operation temporarily only during the transferring, shutting down, and switching.