Conference kali::dewbr

Hi,

Yes , I think you can do this by using the standby track command on 
the Cisco/DECbrouter.

The way HSRP works is that the active router is selected using a 
priority. The standby track command will track the status of a serial 
interface. If the tracked interface went down , the priority would be 
lowered and then the second router would take over. You still need to 
use a routing protocol along with HSRP.

FOr more info look at the following document on Cisco connection 
online :

http://www.cisco.com/univercd/data/doc/cintrnet/ics/icshsrp.htm

There is a not in the Cisco notes conference that tells you about how 
to get access to CCO.

Hope this helps


Michel

    
    Hi Jeannie,
        
    >This customer wants to use either a DECbrouter or a RouteAbout for his
    >primary frame relay links and secondary DECbrouters or RouteAbouts for
    >PSTN/ISDN dial backup.
    
    The first question is, what protocols will be sent across the link?

    >Is this supported on the DECbrouter?

    What it apears your looking to do is a reroute of traffic to another router
    which has dialup capabilities. Depending on the protocols being used you
    could have another router to the same location "route" using dailup based
    on a cost based selection Ie. DECnet, OSPF, IS-IS. For Example with DECnet
    both routers could have a route to the same network but the router with
    dialup has a higher cost associated to it's WAN interface and unless the
    lesser cost router "Frame Relay Link" failed the higher cost path router
    would not bring up its "dialup" link.

    >Is this what HSRP does, or is
    >HSRP only for failure of the primary router and not the links?
     
    HSRP is used if you want to have a "Hot Standby" Router who's only function
    in life is to be the backup router if a primary router's Interface fails.
    This Standby router would be configured exactly the same as the primary
    router and if a designated interface on the primary should fail the Standby
    router's configured interface would assume role and function as the
    primary route until the primary router's link comes back up online.
    HSRP is only used with IP Routing only.

    From DECbrouter 10.3 Docs
    The Hot Standby Router Protocol provides high network availability because 
    it routes IP traffic from hosts on Ethernet, FDDI, or Token Ring networks
    without relying on the availability of any single router. 

    This feature is useful for hosts that do not support a router discovery
    protocol such as IRDP and do not have the functionality to switch to a new 
    router when their selected router reloads or loses power. Because existing 
    TCP sessions can survive the failover, this protocol also provides a more
    transparent means of recovery for hosts that dynamically select a next hop
    for routing IP traffic.

    >Would we need to use any particular routing protocol or floating static
    >routes(?), and how do we set up the secondary router - as a dial-on-demand
    >interface?
    
    If you simply want to use another WAN Interface on a router to establish
    a connection to the remote site and route all traffic from the Primary
    interface to the Secondary when the Primary link fails then both the
    DECbrouter using Dial-Backup and the Routeabout using WAN Restoral can do
    this. However if you need HSRP functionality then the DECbrouter is your
    only option. However since the DECbrouter's Lance Ethernet Chip does not
    allow multiple MAC Addresses then HSRP Groups can't be setup with the
    DECbrouter and HSRP is limited. Also DECbrouters cannot be configured
    for HSRP and DECnet Simultaneously due to both DECnet and HSRP needing to
    modify the MAC Address of the router. 

    Regards,
    Neil Sheehan
    NPS/NSTG Router Support

    

    Thanks Michel and Neil for your advice.
    
    The protocol is IP only.  I don't believe their PCs/hosts are capable
    of changing the default gateway on-the-fly, hence the interest in HSRP.
    
    One thing that is confusing me (even after reading the web page in .1)
    - is HSRP responsive to  loss of a WAN link, or does it only work if the
    router is powered down (which wouldn't be very useful).  If its WAN
    link fails, does the active router send out a HSRP message with a low
    priority so that a standby can take over?
    
    From looking at the standby track command, this tracks the status of
    the standby routers' interfaces and affects which of
    the standby routers will become the active if the active
    router fails - it doesn't seem to apply to the active router's interfaces.
    
    Also, Neil, if the DECbrouter cannot have more than 1 MAC address on
    its interface, how does it participate in HSRP?  Doesn't HSRP mean it
    has to support its own Ethernet MAC in addition to the virtual MAC? 
    And what is the significance of not supporting an "HSRP Group"?
    
    Thanks again
    Jeannie
                                                                  

    >One thing that is confusing me (even after reading the web page in .1)
    >- is HSRP responsive to  loss of a WAN link, or does it only work if the
    >router is powered down (which wouldn't be very useful).

    It's responsive to loss of an interface if it is configured with the
    standby track and priority commands

    The Hot Standby Router Protocol detects when the designated active router
    fails, at which point a selected standby router assumes control of the
    Hot Standby group's MAC and IP addresses. A new standby router is also
    selected at that time.

    To configure an interface so that the router's Hot Standby priority
    changes based on the availability of other interfaces, use the standby
    track interface configuration command. To remove the tracking, use the
    no form of this command.

    standby track type number [interface-priority]
    Ex. standby track Serial 0

    When a tracked interface goes down, the Hot Standby priority of the
    router decreases by 10. If an interface is not tracked, its state changes
    do not affect the Hot Standby priority of the router. For each interface 
    configured for Hot Standby, you can configure a separate list of
    interfaces to be tracked.

    >Also, Neil, if the DECbrouter cannot have more than 1 MAC address on
    >its interface, how does it participate in HSRP?  Doesn't HSRP mean it
    >has to support its own Ethernet MAC in addition to the virtual MAC? 
    >And what is the significance of not supporting an "HSRP Group"?

    The DECbrouter has a burned-in MAC Address and a the LANCE Chip has
    a register which reads this Address. However the register can be
    overwritten with another address other than the default BIA which gets
    read by the LANCE during startup. DECnet modifies this register with
    a DECnet Address, HSRP modifies this address with a MAC address as
    well. Thus you can't have DECnet and HSRP configured on the same
    DECbrouter.

    show int e 0
    Hardware is Lance, address is 0800.2bb3.fb3e (bia 0800.2bb3.fb3e)

    decnet routing 1.1
    int e 0
    decnet cost 4

    Hardware is Lance, address is aa00.0400.0104 (bia 0800.2bb3.fb3e)

    Hope this answers your questions

    Regards,

     Neil.....