IPX Vol.1 Switching Notes

Downstream switches inherit timers from the root (of each VLAN)

  • BPDUgurad blocks incoming BPDUs.
  • BPDUfilter blocks outgoing BPDUs.
  • bpdufilter default and bpduguard default work in conjunction with portfast default.
  • spanning-tree guard loop  is similar to UDLD, but users STP BPDU keepalive.
show spanning-tree mst [detail]
In MST, load-balancing with cost/port-priority is the same as CST, PVST.
interface f0/0
spanning-tree mst 1 cost 1
spanning-tree mst 2 port-p 0

All switches in the L2 transit path should know about the RSPAN remote-vlan, and the interconnections should be trunk. Remember to remove pruning for RSPAN VLAN from trunks.

IPphone tags voice traffic with CoS 5.

switchport voice vlan dot1p instructs the IP-phone to apply VLAN0 and CoS 5, so both Voice & Data share the same VLAN.

switchport voice vlan  automatically applies portfast.

mls qos trust device ciscoipphone means only trust CoS if received from IP-phone which is detected by CDP.

Fallback Bridging is the concept of bridging non-routed protocols between SVIs or native L3 router interfaces on switches. Similar to CBR and IRB on routers.

bridge 1 protocol vlan-bridge
interface f0/1
 bridge 1
  • PVLAN requires Transparent VTP mode.
  • Whenever a task asks us to optimize a switch for memory or routing, it means “sdm prefer routing“
  • Macros do not accept “interface range”!
  • When filtering traffic using mac-access-list remember to allow Spanning-tree and ARP stuff!


  • standby use-bia  : not using the vMAC
  • standby version 2  : Uses for inter-router communications instead of
standby 1 ip
standby 1 priority  : default is 100
standby 1  : not default
standby 1 track 1 decrement  // same as  standby 1 track Serial0/1/0 20

Remember to add static arp for hosts when filtering ARP in LAB exam. (show arp)

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