Difference between "VSS" & "HSRP"

[gauravpundir231]

Hi,

Can anyone please advise : Whats the difference between using VSS and HSRP.

What are the pros and cons of both.

How can we know "when to use VSS" and "when to use HSRP"

[Julio E. Moisa]

Hi

VSS is virtualization technology,  2 devices are seen like only 1. So Spanning tree is not required.

VSS is network system virtualization technology that pools multiple Cisco ® Catalyst ® 6500 Series Switches into one virtual switch, increasing operational efficiency, boosting nonstop communications, and scaling system bandwidth capacity to 1.4 Tbps. At the initial phase, a VSS will allow two physical Cisco Catalyst 6500 Series Switches to operate as a single logical virtual switch called a virtual switching system 1440 (VSS1440)

Reference: http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-6500-virtual-switching-system-1440/prod_qas0900aecd806ed74b.html

About HSRP is used to create high availability between 2 networks creating a virtual IP, this virtual IP will represent the gateway for the network. HSRP works like active and standby, if the active devices go down, the standby device will become in active. It is part of the FHR Protocols.

Please rate the comment if it is useful

:-)

[gauravpundir231]

Hi Julio, Thnx for ur reply.

Can u pls advise how failover takes place in VSS and HSRP

[Julio E. Moisa]

You are welcome, 

About VSS failover, here you will find interesting scenarios:

http://www.ciscozine.com/cisco-vss-failure-scenarios/

Now about HSRP:

HSRP work with active and standby devices, also you could include more devices to be part of the HSRP group, but they will be in listen state. To be honest I have seen maximum 4 devices on the same HSRP group.

HSRP  works with priorities, the higher priority will be used for the active HSRP device, the standby device will have a lower priority than the active device. By default the priority is 100

In order to enable the failover the preempt command is used. The HSRP preemption feature enables the router with highest priority to immediately become the Active device, although it can be configured on the standby devices as well.

Remember, the HSRP groups must be have communication between them, it could be through trunk interfaces or routing protocols. 

An example could be:

PRIMARY DEVICE:

vlan 10

interface vlan 10
ip address 192.168.10.2 255.255.255.0
standby 10 ip 192.168.10.1 
standby 10 preempt
standby 10 priority 105
no shutdown

SECONDARY DEVICE:

vlan 10

interface vlan 10
ip address 192.168.10.3 255.255.255.0
standby 10 ip 192.168.10.1 
standby 10 preempt
no shutdown

Note: the priority is not configured on the secondary device, because the priority 100 (default) is added  implicitly.

You can use the following command to verify the status on a switch (HSRP also works on routers)

show standby vlan 10

Hope it is useful

:-)

[Joseph W. Doherty]

To add to Julio's info, VSS is also supported on the 6500 replacement series, the 6800 series, it's also supported on some of the later 4500 series (and I suspect it will be supported on some of the just announced Catalyst 9000 series).

BTW, another technology somewhat like VSS is the various "stacking" technologies that support some 2960s, 3750s and 3650/3850s (and some Catalyst 9000?).

About HSRP is used to create high availability between 2 networks creating a virtual IP, this virtual IP will represent the gateway for the network.

When Julio mentions "2 networks", I suspect he has in mind physical gateway devices.  As Julio goes on to explain, HSRP provides a virtual gateway IP; one that multiple devices support, but only one device actively supports it (i.e the currently active gateway).  BTW, HSRP is not limited to just running with 2 physical gateway devices.  Also there are several of varieties of HSRP, i.e. v1, mHSRP, v2, and there other FHRPs like GLBP and VRRP.

[legandry2]

thanks for the clear explains 

[AmrEzzat]

hsrp must use a virtual ip , but vrrp can use one of the 2 switches ip , also vrrp only have one master and if down relect the second ,but hsrp has hirarchy if master is down there is the second and the third directly up , last the vrrp is open protocol but its timers is very low, hsrp is cisco propritory but you may need to readjust its timers to be as low as vrrp

vss , stacking with cables, stack wise virtual is more expensive , better throughput ,but stack cables only valid for certain distances with max number of stacked devices like 8 (recommended max is 5)

that is what I know , if there is any error kinly correct it , thanks