Re: MPLS TE Tunnel : Tunnel B/W doubt

Gaurav

Then wat s the significance of Metric command in TE ?

On Sun, Jan 29, 2012 at 11:14 PM, GAURAV MADAN <gauravmadan1177_at_gmail.com>wrote:

> There can be multiple tunnels between a given src and a given dest.
> If all properties of tunnel are same .... This will result in equal path
> load balancing
> If properties like b/w are diff .... Unequal path load balancing will take
> place ..
>
>
>
> On Sun, Jan 29, 2012 at 11:02 PM, CCIE KID <eliteccie_at_gmail.com> wrote:
>
>> Sonu
>>
>> But the Head end Router l will choose only one path to the same Tail End
>> Router with only one Tunnel. Why it chooses two Tunnels ?
>>
>>
>>
>> On Sun, Jan 29, 2012 at 10:12 PM, Sonu Khandelwal <sonu.kwl_at_gmail.com>wrote:
>>
>>> Yes, for two path to the same destination two tunnels will be needed
>>> with two different explicit path.
>>>
>>> "tunnel mpls traffic-eng autoroute metric" to used to change the igp
>>> metric of the tunnel interface. By default tunnel's igp metric is the same
>>> as igp metric b/w source and destination.
>>>
>>> for e.g
>>>
>>> if tunnel source is 1.1.1.1 and tunnel destination is 3.3.3.3. Assume
>>> tunnel is not present and cost to reach from 1.1.1.1 to 3.3.3.3 is 10.
>>>
>>> Now when tunnel comes up, its metric will be 10.
>>>
>>> if you want this metric of 10 to be changed then you can use "tunnel
>>> mpls traffic-eng autoroute metric" to do the same thing.
>>>
>>> Thanks,
>>> Sonu
>>>
>>>
>>> On Sun, Jan 29, 2012 at 9:27 PM, CCIE KID <eliteccie_at_gmail.com> wrote:
>>>
>>>> Gaurav
>>>>
>>>> Dude one new doubt man
>>>>
>>>> To reach a particular Tail end router, there should be only route.
>>>>
>>>> In regular SPF, the result of path computation may be two equal cost
>>>> multipaths (ECMP) to a destination. However, the result of CSPF is always
>>>> one path to the tailend router. In case, two paths are equal, CSPF has 3
>>>> rules followed sequentially to break the tie:
>>>>
>>>> *a.* Take the path with largest minimum available bandwidth
>>>>
>>>> *b.* Take the path with the lowest hop-count (number of routers in the
>>>> path)
>>>>
>>>> *c.* Take one path at random.
>>>>
>>>>
>>>> So there should be only one path to a TAIL END router.. How does it has
>>>> two paths for a same TAILEND router. via two different TE TUNNELS.
>>>>
>>>>
>>>>
>>>> On Sun, Jan 29, 2012 at 8:44 PM, CCIE KID <eliteccie_at_gmail.com> wrote:
>>>>
>>>>> Gaurav
>>>>>
>>>>> Tats gr8 mate .. I will also check the purpose of it and let u know
>>>>> buddy..
>>>>> Till then study hard
>>>>>
>>>>>
>>>>>
>>>>> On Sun, Jan 29, 2012 at 8:33 PM, GAURAV MADAN <
>>>>> gauravmadan1177_at_gmail.com> wrote:
>>>>>
>>>>>> Kid
>>>>>>
>>>>>> Everything you said is exactly what i understand this topic :)
>>>>>> We are on same page .
>>>>>>
>>>>>> I will simulate the usage of metric command and try to post results ,
>>>>>>
>>>>>> Till then .. thnx
>>>>>>
>>>>>> Gaurav Madan
>>>>>>
>>>>>>
>>>>>> On Sun, Jan 29, 2012 at 7:39 PM, CCIE KID <eliteccie_at_gmail.com>wrote:
>>>>>>
>>>>>>> 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)
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> With Warmest Regards,
>>>>>
>>>>> CCIE KID
>>>>> CCIE#29992 (Security)
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> With Warmest Regards,
>>>>
>>>> CCIE KID
>>>> CCIE#29992 (Security)
>>>>
>>>>
>>>>
>>>
>>
>>
>> --
>> With Warmest Regards,
>>
>> CCIE KID
>> CCIE#29992 (Security)
>>
>>
>>
>

-- 
With Warmest Regards,
CCIE KID
CCIE#29992 (Security)
Blogs and organic groups at http://www.ccie.net