In one example, a network device comprising a first chassis of a multi-chassis link aggregation group (MC-LAG) having three or more chassis, comprises one or more network interfaces configured to receive a packet to be forwarded using the MC-LAG, and a control unit configured to determine whether the packet was received from a device outside of the MC-LAG, when the packet was received from the device outside of the MC-LAG, add data to the packet that identifies the first chassis as a source of the packet for the MC-LAG, and forward the packet via at least one of the network interfaces. In this manner, chassis of the MC-LAG can prevent forwarding of the packet to the source of the packet for the MC-LAG, based on the data that identifies a source of the packet for the MC-LAG.

A switch interface board may include a first serializer/deserializer to communicate with a first group of packet processing components of a first chassis via a first port. The first chassis may house the switch interface board and the first group of packet processing components. The switch interface board may include a second serializer/deserializer to communicate with a second switch interface board of the first chassis via a second port. The second switch interface board may be connected to a second group of packet processing components of the first chassis. The second group of packet processing components may be different from the first group of packet processing components. The switch interface board may include a third port to communicate with a third switch interface board of a second chassis or a switching device of a cross-connect chassis.

A stacked switch packet communication system is connected to a Multi-Chassis Link Aggregation Group (MLAG). Devices in the system include a designated device for receiving packets that are destined for the MLAG. A new MLAG device is enabled while continuing packet communication by identifying an address of a single port in the new MLAG device. In first updates of the devices the single port is established in the forwarding databases of the devices and the packets transmitted through the devices to the single port. Thereafter, in second updates the single port is replaced in the forwarding databases by another port of the new MLAG device. Upon completion of respective second updates, the packets are transmitted through the devices to the other port in the MLAG.

Examples disclosed herein relate to a grace link state advertisement (LSA) from a virtual stack device. In an example, a first member network device of a virtual stack device may an input from a Multi-Active Detection (MAD) device. The virtual stack device may be a logical network device comprising the first member network device and a second member network device. Based on the input from the MAD device, the first member network device may determine whether a grace link state advertisement (LSA) is to be sent to a neighbor Open Shortest Path First (OSPF) enabled router by the first member network device, wherein the neighbor OSPF enabled router is an OSPF neighbor to the virtual stack device.

A stacked switch packet communication system is connected to a Multi-Chassis Link Aggregation Group (MLAG). Devices in the system include a designated device for receiving packets that are destined for the MLAG. A new MLAG device is enabled while continuing packet communication by identifying an address of a single port in the new MLAG device. In first updates of the devices the single port is established in the forwarding databases of the devices and the packets transmitted through the devices to the single port. Thereafter, in second updates the single port is replaced in the forwarding databases by another port of the new MLAG device. Upon completion of respective second updates, the packets are transmitted through the devices to the other port in the MLAG.

A data packet from a sub-virtual routing and forwarding (sub-VRF) in a virtual routing and forwarding (VRF) is received. The VRF includes more than one sub-VRF. A value in a Border Gateway Protocol (BGP) attribute attached to the data packet is determined. Based on the value in the BGP attribute, whether to route the data packet to a different sub-VRF in the VRF is determined.

One embodiment of the present invention provides a switch. The switch is configurable to be a member of a first fabric switch. The switch includes a link aggregation module. During operation, the link aggregation module marks an ingress-switch field of a frame with a virtual switch identifier. This virtual switch identifier is associated with the switch and a second switch, which is a member of a second fabric switch, and is from a range of identifier associated with the first fabric switch and the second fabric switch. Each of the first fabric switch and the second fabric switch is operable to accommodate a plurality of switches and operate as a single switch.

A method, an information handling system (IHS) and a switching system for preventing communication loops in an IHS. The method includes identifying, via a controller, at least one stacking port in a first switch of a first chassis. The first switch is in communication with a second switch of a second chassis via a first link. At least one stacking port is configured as an unblocked port. Port blocking and unblocking actions are determined for the at least one stacking port. The at least one stacking port is configured based on the determined port blocking and unblocking actions and a determination is made if the first chassis is a root bridge chassis having at least one uplink port. In response to the first chassis being a root bridge chassis, a first uplink port in the first switch is configured as an unblocked port.

A virtual network device includes several different virtual network device sub-units, which collectively operate as a single logical network device. An interface bundle includes interfaces in more than one of the different virtual network device sub-units included in the virtual network device. The interface bundle is coupled to a virtual link bundle, which connects the virtual network device to another device. The interface bundle is managed as a single logical interface.

In one embodiment, a stack manager of an operating system on a network device configures an egress abstract stack port and an ingress abstract stack port, where the configuring maps one or more physical ports of the network device to a corresponding abstract stack port. The stack manager then transmits platform-independent egress stack discovery messages on the egress abstract port to a remote ingress abstract stack port of an adjacent stack member, and receives platform-independent ingress stack discovery messages on the ingress abstract port from a remote egress abstract stack port of an adjacent stack member. The stack manager may then provide platform-independent stacked network device operation using connectivity between the egress abstract stack port and remote ingress abstract stack port, and connectivity between the remote egress abstract stack port and ingress abstract stack port.