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CCNP BCMSN Notes – Securing Switch Access
Monday, November 9th, 2009Port Security
Port security can be used to restrict which or how many hosts connect to a switch port:
Tags: BCMSN Notes
CCNP BCMSN Notes – Advanced Spanning Tree Protocol
Thursday, November 5th, 2009Rapid STP (RSTP)
RSTP was developed to provide a faster converging alternative to STP, and is defined in IEEE 802.1w.
Like STP, RSTP can be applied as a single instance or per VLAN.
A root is elected by lowest bridge ID, as in 802.1D STP.
Tags: BCMSN Notes, STP
CCNP BCMSN Notes – Protecting the Spanning Tree Protocol Topology
Thursday, November 5th, 2009Root Guard
If a switch with a lower bridge ID enters the network, it can preempt the current STP root.
Root guard can be enabled on an interface to prevent it from becoming a root port:
Root guard will affect all VLANs on the port.
Tags: BCMSN Notes, Switching
CCNP BCMSN Notes – Spanning Tree Configuration
Tuesday, November 3rd, 2009Root Bridge Configuration
The root bridge should be positioned centrally in the network to ensure the spanning tree forms in a predictable manner.
Two bridge ID formats are available:
802.1D Standard – 16-bit priority + unique MAC address for the VLAN
802.1t Extended – 4-bit priority multiplier + 12-bit VLAN ID + non-unique MAC address
Tags: BCMSN Notes, [...]
CCNP BCMSN Notes – Traditional Spanning Tree Protocol
Tuesday, November 3rd, 2009STP is defined in IEEE 802.1D.
BPDUs
STP messages are carried by Bridge Protocol Data Unit (BPDU) frames; BPDUs are multicast to 01:80:c2:00:00:00.
BPDU types:
Configuration – Used for spanning-tree computation
Topology Change Notification (TCN) – Used to announce changes in the network
Tags: BCMSN Notes, STP
CCNP BCMSN Notes – Aggregating Switch Links
Friday, October 30th, 2009EtherChannel Load Balancing
EtherChannel distributes load across multiple physical links by examining between one and three low order bits of an arbitrary address. XOR is used when multiple addresses are examined.
Address types eligible for examination:
Tags: BCMSN Notes, Load Balancing
CCNP BCMSN Notes – VLAN Trunking Protocol
Friday, October 30th, 2009VTP modes:
Client – Rely on VLAN information advertised by a server; no local configuration possible
Server – Have full control over VLAN creation and modification for the VTP domain
Transparent – Does not participate in VTP but will forward advertisements
Tags: BCMSN Notes, Trunking, VLAN
CCNP BCMSN Notes – VLANs and Trunks
Friday, October 30th, 2009The normal range allows for VLANs 1 -1005; IEEE 802.1Q expands this to 1 – 4095.
VTP version 1 and 2 only support VLANs 1 – 1005. VTPv3 will support extended VLANs but isn’t available yet.
Dynamic VLANs can be configured by a VLAN Membership Policy Server (VMPS).
Trunk types:
Tags: BCMSN Notes, Trunk, VLAN