Cisco Technology, Inc.

Siddharth Kasat

Christian Sasso

Ronak K Desai

Ankur Goyal

Yibin Yang

Amitkumar V Patel

Anand Hariharan

Shivaranjani Sankara Krishnan

Hariharan Balasubramanian

Kishan Kumar Kotari Uppunda

Hari Balasubramanian

Kishan Kumar Kotari Uppanda

Upon receiving a first message, from the second network device, indicating that the second network device is incompatible with one or more virtual local area network (VLAN) pruning techniques, a timer on a first network device is configured to expire after a predetermined period of time. The first network device is configured to maintain a subscription for the second network device to one or more VLANs until the timer expires. The second network device is configured to transmit the first message in response to detecting an upcoming control plane outage at the second device. Prior to the timer expiring, embodiments transmit data assigned to the one or more VLANs to the second network device. Embodiments also periodically receive update messages, from the second network device, identifying one or more VLANs to which the second network device wants to subscribe.

Hitless pruning protocol upgrade on single supervisor network devices

Certain embodiments of the present disclosure generally relate to allocating a sub-area of Fiber Channel addresses (FCIDs) to a device. A range of addresses may be assigned to the device using a mask address, where the most significant bits represent a mask and the least significant bits represent a sub-range of FCIDs available to be assigned to the device. Therefore, routing information may be stored efficiently in a Ternary Content Addressable Memory (TCAM) by storing a single entry in the TCAM for each sub-area of FCIDs allocated to a device, instead of storing an entry for each FCID. The single entry may indicate the mask address and the width of the mask.

Sub-area FCID allocation scheme

In Service Software Upgrade (ISSU) permits administrators to upgrade the control plane software of a network device without any disruption to the traffic passing through the data plane of the network device. However, because the control plane is unavailable, the network device is unable to transmit periodic messages to re-subscribe to specific VLANs. This may result in a service outage in end devices that rely on the network device to receive data assigned to those VLANs. To prevent the network device from being unsubscribed from the VLANs while the control plane is unavailable, the network device may transmit a control plane message before starting ISSU. Once a neighboring network device receives the message, the neighboring device delays unsubscribing the network device until the control plane is again available. Thus, the network device may perform ISSU without the possibility of data traffic not reaching end devices.

The number of domain identifiers is incrementally increased for use by a switch in an established fiber channel switched fabric. In other words, the number of domains assigned to a switch by the Principal Switch of the fiber channel switched fabric is increased without triggering the reconfiguration of the established fiber channel switched fabric. In one implementation, incrementally adding one or more additional domain identifiers includes requesting said one or more additional domain identifiers from a Principal Switch of the fiber channel switched fabric using a different World Wide Name (WWN) than used to acquire the original one or more domain identifiers used by the switch.

Increasing the number of domain identifiers for use by a switch in an established fibre channel switched fabric

According to one aspect, a Fiber Channel (FC) switch that is currently serving as a Principal Switch among a plurality of FC switches in a FC Fabric sends an Exchange Fabric Parameters (EFP) frame having an empty domain identifier list to neighboring FC switches during a first portion a Principal Switch Selection phase. During a second portion of the Principal Switch Selection phase that is after the first portion, the first Fiber Channel switch sends to neighboring FC switches an EFP frame having a non-empty domain identifier list to indicate to the neighboring FC switches that the first FC switch is to remain serving as the Principal Switch in the FC Fabric.

Persistent principal switch for fibre channel fabric

A Fiber Channel (FC) switch and related methods are provided for merging the FC switch with an existing FC network. During a merge process of a stand-alone switch with an FC network, a first Exchange Fabric Parameters (EFP) frame is sent from the stand-alone switch to an FC switch in the existing FC network. The first EFP frame has an empty domain identifier (ID) list. The stand-alone switch receives a second EFP frame from the FC switch. The second EFP frame contains a domain ID list of domain IDs already in use in the FC network. The stand-alone switch compares the domain ID list in the second EFP frame with a stored list of one or more domain IDs associated with the stand-alone switch to determine if there is a domain ID overlap or conflict. If no conflict is detected, the stand-alone switch merges with the existing network without initiating a Build Fabric phase or a Principal Switch Selection phase that could cause disruption of traffic in the network.

Merging a stand-alone switch to a fibre channel network

Methods and apparatus for reconfiguring a fabric associated with a storage area network (SAN) are disclosed. According to one aspect of the present invention, a method includes undergoing an update process, the update process being arranged to update software associated with a switch. The switch is included in a SAN fabric. The method also includes determining when the update process is completed, and ascertaining whether there is at least one state change associated with the SAN fabric when the update process is completed. Finally, the method includes initiating a recovery action in the SAN fabric if there is at least one state change associated with the SAN fabric.

Method and apparatus for implementing a recovery action in response to a state change in a storage area network

A Fiber Channel switch is provided for a relative addressing scheme for domain values to avoid losing portions of a Fiber Channel identifier. At a Fiber Channel switch, data is stored that assigns a relative domain field value to a run-time domain. The relative domain field value used for a Fiber Channel identifier is determined for devices connected to the switch based on the run-time domain of the devices and the virtual storage area network in which the devices are active. A Fiber Channel identifier is stored in a memory of the switch that comprises the relative domain field value determined for the device together with area and port values for the device. The relative domain value is either a reserved domain field value for an existing virtual storage area network or any of the regular domain field values for a new virtual storage area network.

Domain-independent persistent fibre channel identifiers

In one embodiment, a technique for returning Domain IDs to a Fiber Channel fabric without a full build fabric (BF) phase is provided. A switch in the fabric may send a principal switch a message requesting the return of one or more Domain IDs assigned to that device. The principal switch may update the list of fabric Domain IDs to remove the Domain IDs identified in the message and send the updated list to devices in the fabric.

Returning domain identifications without reconfiguration

In one embodiment, a technique for returning Domain IDs to a Fibre Channel fabric without a full build fabric (BF) phase is provided. A switch in the fabric may send a principal switch a message requesting the return of one or more Domain IDs assigned to that device. The principal switch may update the list of fabric Domain IDs to remove the Domain IDs identified in the message and send the updated list to devices in the fabric.

In one embodiment, a technique for performing partial build fabric operations when merging two or more Fibre Channel fabrics is provided. By maintaining a Principal Switch already assigned for one of two merging fabrics, a limited 'partial build' may be performed for the other merging fabric. As a result, the time required for a Principal Switch selection phase may be greatly reduced.

Partial build of a fibre channel fabric

In one embodiment, detecting an initialization of a synchronization phase of a network device in a fiber channel fabric, performing synchronization phase optimization of the network device to select a predetermined number of interfaces, and transmitting a synchronization request on the predetermined number of interfaces, are provided.

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Santa Clara, CA, United States of America

Siddharth Kasat