CCNP switch slides 5 Flashcards
source
http://quizlet.com/3373182/ccnp-switch-deck-5-flash-cards/
How does packet forwarding work
arp for local subnet, if on different subnet, will arp for dgw
what is a proxy arp?
for hosts that doesn’t understand routing, the DGW is configured to reply with its own mac
Define HSRP
Host Standby Router protocol. Cisco proprietary. Switch is either active, standby, or listen
What address does HSRP send hello packets to?
224.0.0.2 (all routers)
What is the range of HSRP group numbers?
0-255
What is unique about HSRP group numbers?
They are locally significant on an interface. HSRP1 on one VLAN is different from HSRP1 on another
How does HSRP election work?
based on priority (0-255). Default is 100. Highest IP is tie breaker
What are the 6 HSRP states?
disabled, init, listen, speak, standby, active
What does the standby HSRP router do?
Only the standby monitors the hello messages from the active router
How often are HSRP hellos sent?
3 seconds. Holdtime =3 hellos + 1
What happens during HSRP failover?
The standby becomes active and stays active by default. Preemption can be configured
What does the minimum keyword do in HSRP?
forces the router to wait for a period of time before attempting overthrow
What does the reload keyword do in HSRP?
forces the router to wait for a period of time after the switch is reloaded before attempting to overthrow
What types of authentication does HSRP allow?
plain text or md5
How does HSRP plain text authentication work?
a key string of up to 8 characters is sent. Default is cisco.
How does HSRP do MD5 authentication?
by using a hash of a key string
What are the steps to configuring HSRP MD5 authentication?
1-name the chain, 2-establish a key number, 3-create the key string, 4-apply the chain to the string
How does HSRP port tracking work?
When a specific interface is tracked, HSRP reduces it’s priority after a specified interval.
What are the caveats for HSRP port tracking?
Another router must have a higher HSRP priority and have preemt set up
How does HSRP gateway addressing work
Each physical interface has a different IP address. All physical interfaces point to a virtual interface called the standby address or VIP
How is the HSRP MAC address configured?
0000.0c07.acxx where xx is the group number as a 2-digit hex value
How can you load-balance with HSRP?
create 2 hsrp groups, each with the active router being different switches, then have clients point to each
How do you show HSRP status
show standby
How does every HSRP config command begin?
switch(config-if)# standby xx where x= group number
How does the standby handle ARP issues after it becomes active?
by sending a gratuitous ARP
Define VRRP
Virtual Router Redundancy Protocol, pretty much the same as HSRP
What is a VRRP group?
the same as a standby group in HSRP
How does every VRRP command begin?
switch(config-if)# vrrp xx where xx= group number
What is the VRRP master router?
the active router. All other routers are in backup state
What are the VRRP group and priority numbers?
group (0-255), priority (1-254 254 is highest, 100 default)
What is the format of the VRRP virtual MAC?
0000.5e00.01xx
How often are VRRP advertisements sent?
1 second. Backup routers can learn the interval from the master
How do VRRP routers handle preemption?
on by default
How does VRRP do tracking?
it can’t
Where does VRRP send advertisements?
multicasts to 224.0.0.18 (VRRP)
How does the VRRP master router handle the VIP?
the master router can share the VIP
What is the VRRP skew time?
Hold time is 3xhello. A skew time of 256ms-routerpriority)/256ms is added
Define GLBP
Gateway load balancing protocol, cisco proprietary
How does every GLBP command begin
switch(config-if)# glbp xx where xx = group number
How does GLBP work?
Routers are assigned to common GLBP group. All routers can be active and can load balance
