Re: MPLS TE Tunnel : Tunnel B/W doubt

Gaurav

TE Auto Route Announce will just make ur OSPF learned LSA's from the Tunnel
Tail End to utitlize the Tunnel path to reach all the networks behind the
Tunnel Tail End Router. It has nothing to do with priority levels for each
tunnel
U can assign priorities to each tunnel and then tat take over the
appropriate B.W. available in the interface if it has highest priority

In ur case both ur tunnels has both set up and hold priority has 7 and 7
7 and 7 is the least priority tat u can assign to a tunnel and both the
tunnels has the same priority and both r pointing to the same tunnel tail
end and also u r running Auto Route Announce on both the tunnels

But the only difference between the two tunnels is the Bandwidth and to
form the two tunnels it requires 60 and 70 kbps end to end to form the
tunnel. So atleast the B.W of the end to end path should be atleast 130kpbs

So now OSPF will carry the TE information like the requested B.W and also
other TE colors associated with TE in its Opaque LSA Type 9 ,10 and 11.
depends upon it is a Single Area OSPF or Multi Area and also it is within
the Single AS. If the Head end sees that it has enough B.W. then the Path
message from Head end to Tail End and Reserve message from the Tail End to
head End is succesfull , the tunnel will be up.

if there is any change in the available BW in that particular end to end
path, it will be conveyed by OSPF and it triggers the Path message and
Reserve message

In ur setup

U r obviously u r going to see two paths to reach the tail-end router via
these two tunnels and there will be Unequal cost LOAD balancing . If u want
to prioritize one tunnel over another one , just change the metric of the
tunnel rather than the BW
Because B.W inside the tunnel doesnt reflect ur BEST METRIC to reach a
particular TE Tail End

So ultimately u have many paths to the Same tail end router ie via
different tunnels.So ultimately it all depends upon how much BW is required
to form the tunnel . Int his case , there will 70:60 ratio of traffic going
from one tunnel to another tunnel.

If u dont want to see Unequal Cost Load Balancing, u have to do Policy
Routing rather than using AutoRoute Announce.

But I am not sure about this command

tunnel mpls traffic-eng autoroute metric

If u give this command whether one tunnel will be preferred over another
tunnel if ur Tail End Router address are same.

Post me about this command dude

Hope this helps

On Sun, Jan 29, 2012 at 1:24 AM, Naveen <navin.ms_at_gmail.com> wrote:

> Yes. What you have is already doing UELB (unequal cost load balancing in
> the ratio 6:7) also across TE tunnels. Try sending some traffic end to end,
> and check the TE counters.
>
> If your intention is not to load balancing at all, then remove "autoroute
> announce", and then route traffic to the tunnel you want with a local
> policy.
>
>
> On Sat, Jan 28, 2012 at 11:31 AM, GAURAV MADAN <gauravmadan1177_at_gmail.com
> >wrote:
>
> > Naveen ,
> >
> > Thnx for the reply ..
> > Do you mean to suggest some kind of unequal load-balancing across various
> > TE tunnels .
> >
> > Between the tunnels ; I can choose using following command :
> >
> > Router(config-if)#tunnel mpls traffic-eng autoroute metric
> >
> > I can set one tunnel as lower metric to be announced over the second
> > tunnel . and hence play around with this
> >
> > Is that what u r suggesting ?
> >
> >
> > Gaurav Madan
> >
> >
> >
> > On Sun, Jan 29, 2012 at 12:32 AM, Naveen <navin.ms_at_gmail.com> wrote:
> >
> >> What you are seeing is Load balancing across multiple TE tunnels for
> >> prefixes reachable further down the tunnel. This is an expected behavior
> >> with "autoroute announce". You can use "auto-bw" to dynamically control
> the
> >> TE tunnel Bandwidth after tunnel setup.
> >>
> >> Once tunnels are established (using CSPF), IGP considers the Tunnels as
> >> always 1-hop (and always prefers over any other IGP 1-hop path). You can
> >> load balance upto 8,16, or 32 TE paths as supported by the platform.
> >>
> >>
> >>
> >> On Sat, Jan 28, 2012 at 10:13 AM, Sonu Khandelwal <sonu.kwl_at_gmail.com
> >wrote:
> >>
> >>> [image: Boxbe] <https://www.boxbe.com/overview> Sonu Khandelwal (
> >>> sonu.kwl_at_gmail.com) is not on your Guest List<
> https://www.boxbe.com/approved-list>| Approve
> >>> sender <https://www.boxbe.com/anno?tc=10557674166_204049186> | Approve
> >>> domain <https://www.boxbe.com/anno?tc=10557674166_204049186&dom>
> >>>
> >>> on interface it means how much bandwidth can be reserved by RSVP.
> >>> on tunnel it means, how much bandwidth is required by tunnel.
> >>>
> >>> Hope it helps.
> >>>
> >>> Thanks,
> >>> Sonu
> >>>
> >>> On Sat, Jan 28, 2012 at 11:37 PM, GAURAV MADAN <
> >>> gauravmadan1177_at_gmail.com>wrote:
> >>>
> >>> > Then what does "rsvp bandwidth <> " on interface does ?
> >>> > That is also a constraint on interface to establish the tunnel ..
> >>> right ?
> >>> >
> >>> > How do you differentiate between the BW that we specify on interface
> >>> level
> >>> > and the one that we specify on interface tunnel ?
> >>> >
> >>> > Thnx
> >>> > Gaurav Madan
> >>> >
> >>> > On Sat, Jan 28, 2012 at 9:23 PM, Paul Negron <negron.paul_at_gmail.com>
> >>> > wrote:
> >>> >
> >>> > > The bandwidth is a constraint. It only says " I need 60K of
> >>> bandwidth in
> >>> > > order to establish this tunnel". One tunnel requires 60K and the
> >>> other
> >>> > > requires 70K. If the bandwidth is available for both, they will
> both
> >>> be
> >>> > > established. That "bandwidth" constraint has nothing to do with the
> >>> cost
> >>> > of
> >>> > > the tunnel for route selection.
> >>> > > --
> >>> > > Paul Negron
> >>> > > CCIE# 14856 CCSI# 22752
> >>> > > Senior Technical Instructor
> >>> > >
> >>> > >
> >>> > >
> >>> > > > From: GAURAV MADAN <gauravmadan1177_at_gmail.com>
> >>> > > > Reply-To: GAURAV MADAN <gauravmadan1177_at_gmail.com>
> >>> > > > Date: Sat, 28 Jan 2012 20:44:46 +0530
> >>> > > > To: Cisco certification <ccielab_at_groupstudy.com>
> >>> > > > Subject: MPLS TE Tunnel : Tunnel B/W doubt
> >>> > > >
> >>> > > > Hi All
> >>> > > >
> >>> > > > I am running in some issue to understand how Tunnel Bandwidth
> >>> works .
> >>> > > >
> >>> > > > Topology
> >>> > > > ---------
> >>> > > >
> >>> > > > R1 R4
> >>> > > > | |
> >>> > > > | |
> >>> > > > R2-----------------R3
> >>> > > >
> >>> > > > R1 is head end of tunnel . It has 2 tunnels Tunnel0 and Tunnel 1
> as
> >>> > > follows
> >>> > > > :
> >>> > > >
> >>> > > > R1#sh run int tun 0
> >>> > > > Building configuration...
> >>> > > >
> >>> > > > Current configuration : 284 bytes
> >>> > > > !
> >>> > > > interface Tunnel0
> >>> > > > ip unnumbered Loopback0
> >>> > > > tunnel mode mpls traffic-eng
> >>> > > > tunnel destination 4.4.4.4
> >>> > > > tunnel mpls traffic-eng autoroute announce
> >>> > > > tunnel mpls traffic-eng priority 7 7
> >>> > > > tunnel mpls traffic-eng bandwidth 70
> >>> > > > tunnel mpls traffic-eng path-option 1 dynamic lockdown
> >>> > > > end
> >>> > > >
> >>> > > > R1#sh run int tun 1
> >>> > > > Building configuration...
> >>> > > >
> >>> > > > Current configuration : 284 bytes
> >>> > > > !
> >>> > > > interface Tunnel1
> >>> > > > ip unnumbered Loopback0
> >>> > > > tunnel mode mpls traffic-eng
> >>> > > > tunnel destination 4.4.4.4
> >>> > > > tunnel mpls traffic-eng autoroute announce
> >>> > > > tunnel mpls traffic-eng priority 7 7
> >>> > > > tunnel mpls traffic-eng bandwidth 60
> >>> > > > tunnel mpls traffic-eng path-option 1 dynamic lockdown
> >>> > > >
> >>> > > >
> >>> > > >
> >>> > > > Now ; one tunnel has bandwidth of 70Kbps and other has of 60Kbps
> .
> >>> > > > Following is my show ip route ospf output :
> >>> > > >
> >>> > > > 4.0.0.0/32 is subnetted, 1 subnets
> >>> > > > O 4.4.4.4 [110/4] via 4.4.4.4, 00:05:52, Tunnel1
> >>> > > > [110/4] via 4.4.4.4, 00:05:52, Tunnel0
> >>> > > >
> >>> > > > I see both entries there ...
> >>> > > >
> >>> > > > Is there a reason for this ?
> >>> > > > Please let me know .. I think that it should be routing via
> Tunnel
> >>> 0
> >>> > > only .
> >>> > > >
> >>> > > > Thanks
> >>> > > > Gaurav Madan
> >>> > > >
> >>> > > >
> >>> > > > Blogs and organic groups at http://www.ccie.net
> >>> > > >
> >>> > > >
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-- 
With Warmest Regards,
CCIE KID
CCIE#29992 (Security)
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