The OSI Model

Upper Layers

Layers 7 through 4 comprise the upper layers of the OSI protocol stack. They are more geared to the type of application than the lower layers, which are designed to move packets, no matter what they contain, from one place to another.

Linux bonding modes

Mode 0: Balance Round-Robin (balance-rr)
Round-robin policy: Transmit packets in sequential order from the first available slave through the
last. This mode provides load balancing and fault tolerance.

Mode 1: Active-Backup
Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond’s MAC address is externally visible on only one port (network adapter) to avoid confusing the switch.In bonding version 2.6.2 or later, when a failover occurs in active-backup mode, bonding will issue one or more gratuitous ARPs on the newly active slave. One gratuitous ARP is issued for the bonding master interface and each VLAN interfaces configured above
it, provided that the interface has at least one IP address configured. Gratuitous ARPs issued for VLAN interfaces are tagged with the appropriate VLAN id.This mode provides fault tolerance. The primary option, documented below, affects the behavior of this mode.

What is: BPDU filter? – bpdufilter

BPDUs are the messages exchanged between switches to calculate the spanning tree topology. BPDU filter is a feature used to filter sending or receiving BPDUs on a switchport.

It is extremely useful on those ports which are configured as portfast ports as there is no need to send or receive any BPDU messages on of these ports.

Category Archives: Cisco

The OSI Model

Linux bonding modes

What is: BPDU filter? – bpdufilter

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