The MPLS WG Archive

[riza.cetin@alcatel.be]

Ina,

See my reply in line.

Ina Minei wrote:

>
> 2) Confusion regarding the values of oneToOneBackup and
>    facilityBackup.
>
> mplsFrrDetourIncoming
> "The number of detour LSPs originating at this PLR if
>          mplsFrrConstProtectionMethod is set to oneToOneBackup(1).
>          This object MUST return 0 if the mplsFrrConstProtectionMethod
>          is set to facilityBackup(2)."
>
> >From this I understand that the values are oneToOneBackup(1),
> facilityBackup(2).
>
> However, the definition is different:
>
> mplsFrrConstProtectionMethod OBJECT-TYPE
>        SYNTAX        INTEGER { oneToOneBackup(0),
>                                facilityBackup(1)
>

Agreed. We need to correct the definition of the object.

>
> The same values of 1 and 2 appear in the description of other
> variables, such as mplsFrrDetourOutgoing.
>
> Also I was wondering why "none" was not a valid value for
> mplsFrrConstProtectionMethod, it would seem to make sense as well.
>

I actually don't see the reason to set this object to value "none". In which case
you would use value "none"?
Do you plan to use it to disable FRR at the system level?

>
> ----------------------
> 4) Question - Properties of mplsFrrConstEntry
>
> mplsFrrConstEntry OBJECT-TYPE
>        SYNTAX        MplsFrrConstEntry
>        MAX-ACCESS    not-accessible
>        STATUS        current
>        DESCRIPTION
>          "An entry in this table represents detour LSP or bypass tunnel
>           setup constraints for a tunnel instance to be protected by detour
>           LSPs or a tunnel.
>
>           Agents must allow entries in this table to be
>           created only for tunnel instances that require fast-reroute.
>           Entries indexed with mplsFrrConstIfIndex set to 0 apply to all
>           interfaces on this device for which the FRR feature can operate
>           on."
>
> Why do we want to have the properties of the tunnel instance instead
> of the constraints for the tunnel itself?
>

This is due to the fact that each instance of a tunnel can have different
properties, and different FRR requirements.

>
> -------------------
> 5) Question on the tunnel index
>
>  mplsFrrConstTunnelIndex OBJECT-TYPE
>        SYNTAX        MplsTunnelIndex
>        MAX-ACCESS    not-accessible
>        STATUS        current
>        DESCRIPTION
>          "Uniquely identifies a tunnel for which fast reroute is
>           requested."
>        ::= { mplsFrrConstEntry 2 }
>
>     mplsFrrConstTunnelInstance OBJECT-TYPE
>        SYNTAX        MplsTunnelInstanceIndex
>        MAX-ACCESS    not-accessible
>        STATUS        current
>        DESCRIPTION
>          "Uniquely identifies an instance of this tunnel for which fast
>           reroute is requested.
>
>          - lower 16 bits : protected tunnel instance
>          - higher 16 bits: must be all zeros"
>        ::= { mplsFrrConstEntry 3 }
>
> mplsFrrConstTunnelIndex OBJECT-TYPE - what would be the required value here?
>

This object will contain the index of the protected tunnel (assigned during the
configuration of the protected tunnel at the ingress LSR). Refer to
mplsTunnelTable defined in MPLS-TE-MIB.

>
> ----------------
> 6) Question on protection type
>
>  mplsFrrConstProtectionType OBJECT-TYPE
>        SYNTAX        INTEGER { none(0),
>                                linkProtection(1),
>                                nodeProtection(2)
>                              }
>        MAX-ACCESS    read-create
>        STATUS        current
>        DESCRIPTION
>          "Indicates type of the resource protection."
>        DEFVAL { nodeProtection }
>        ::= { mplsFrrConstEntry 4 }
>
> Why do we have the value of "none" defined here? Isn't this for an
> entry that represents either a detour or a bypass? Then how can there
> be no protection?
>

We should remove value "none".

>
> --------------
> 7) Typo (sorry of nitpicking)
> mplsFrrTunARHopEntry  OBJECT-TYPE
>        SYNTAX             MplsFrrTunARHopEntry
>        MAX-ACCESS         not-accessible
>        STATUS             current
>        DESCRIPTION
>          "This entry contains fast-reroute protection status of a signle
>                                                                  ^^^^^^^
>

OK.

>
> -------------------
>
> 9) Questions on One2one backup
>
> We don't have a variable that specifies the bw on the detour. Don't we
> need one?
>

Detour LSPs are also represented in the MPLS-TE-MIB. One entry is created in the
mplsTunnelTable for each detour. This is because that we don't want to replicate
the objects defined in the MPLS-TE-MIB for the detour LSPs. The BW of the detour
should be available in the mplsTunnelResource table entry corresponding to the
detour entry of the mplsTunnelTable.

>
> There are no notifications for the 1-to-1 backup. Wouldn't we want to
> track when an lsp starts using the detour and when it stops using it?

I agree that these traps are missing. We should add them to the next version.
Could you make a proposal?