Re: Load balancing

Trying to boil this down... my interpretation is:

Load Sharing uses any candidate path, not necessarily 'equal' or
'switched', directly connected or not, to distribute traffic. I use
the term Load Sharing as being able to share links over diverse paths,
to ANY destination - an example may be multi-homed ISP links

Load Balancing will distribute/balance traffic between adjacent peers
across multiple links, not routing. I interpret Load Balancing as
sending traffic across multiple paths, to the SAME destination - an
example may be a bundle or server farm, perhaps

I was (and am still) confused when I see a vendor state that a routing
protocol will do 'unequal cost load balancing', I think they mean load
sharing, a load either way? Hearing some vendors speak of these terms
they do seem interchangeable to me at times. The more I hear the less
I understand :)

...As for BGP (or any other routing protocol) my understanding is that
they do not load balance, they ask the RIB, the RIB can balance or
pass the buck.

I thought replying to this might help me understand, but I may be more
confused than I was prior to this post?

~M

On Jul 18, 2009, at 5:43 PM, Gary Duncanson wrote:

> There is also a subtle difference between load balancing and load
> sharing so far as BGP is concerned. At least from what I remember
> from Dr Pete Welcher's papers.
> ----- Original Message ----- From: "Ruhann" <groupstudy_at_ru.co.za>
> To: "Pavel Bykov" <slidersv_at_gmail.com>
> Cc: "jack daniels" <jckdaniels12_at_gmail.com>; "Zaid Alwasity" <zaidalwasity_at_hotmail.com
> >; "Cisco certification" <ccielab_at_groupstudy.com>
> Sent: Saturday, July 18, 2009 10:24 PM
> Subject: Re: Load balancing
>
>
>> As Pavel correctly pointed out, there are many ways on this
>> particular topic
>> :)
>>
>>
>> On Tue, Jul 7, 2009 at 6:20 PM, Pavel Bykov <slidersv_at_gmail.com>
>> wrote:
>>
>>> No... I never said that. There are many ways to load balance.
>>> On CPU, on L3, on routing protocol level, on L4, on L7... No time
>>> to look
>>> for all the links right now.
>>> etherchannel, mac address distribution (like GLBP), hardware cef,
>>> software
>>> cef, ace...
>>>
>>> On Tue, Jul 7, 2009 at 6:14 PM, jack daniels
>>> <jckdaniels12_at_gmail.com>
>>> wrote:
>>>
>>> > Hi,
>>> >
>>> > So that means the only way to load share traffic is CEF ?
>>> > Request you to fwd some links on how this load balancing happens
>>> and > what
>>> > all techiniques are available for load balancing.
>>> >
>>> > Reagrds
>>> > J.Daniels
>>> >
>>> >
>>> > On Tue, Jul 7, 2009 at 9:29 PM, Pavel Bykov <slidersv_at_gmail.com>
>>> wrote:
>>> >
>>> >> Pretty much.
>>> >>
>>> >> Control Plane:
>>> >> 1. Routing protocol decides that routes are equal cost (including
>>> static)
>>> >> and offers them to the routing table (up to preset limit.
>>> Default: 4,
>>> max:6)
>>> >> 2. Routing table installs all offered routes up to preset limit
>>> >>
>>> >> Data Plane:
>>> >> 1. CEF FIB is programmed from the routing table, resolves all
>>> adjacencies
>>> >> (GLEAN entries for ARP) etc.
>>> >> 2. Redundant entries are installed with sharing in mind
>>> >>
>>> >> Data plane forwards the packets, and it's CEFs task to load
>>> balance.
>>> >> CEF cannot use flow mask in most cases, only source/
>>> destination pair
>>> and
>>> >> optionally ID (sort of seed).
>>> >>
>>> >>
>>> http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_command_reference_chapter09186a0080417d88.html#wp1010171
>>> >>
>>> >>
>>> >>
>>> >>
>>> >> On Tue, Jul 7, 2009 at 4:48 PM, jack daniels <jckdaniels12_at_gmail.com
>>> >wrote:
>>> >>
>>> >>> Hi,
>>> >>>
>>> >>> Please suggest -
>>> >>> so routing protocol bring the two routes in routing table for
>>> >>> processor
>>> >>> to read and to load balance TRAFFIC we need CEF .... Cef will
>>> load
>>> balance
>>> >>> traffic per flow and per destination.
>>> >>>
>>> >>>
>>> >>> Regards
>>> >>>
>>> >>>
>>> >>>
>>> >>> On Tue, Jul 7, 2009 at 1:55 PM, Zaid Alwasity <
>>> zaidalwasity_at_hotmail.com>wrote:
>>> >>>
>>> >>>> Hi all,
>>> >>>>
>>> >>>> I think that load sharing means dividing the load manually
>>> between
>>> >>>> multiple
>>> >>>> device for example ,network 1-5 are served through router
>>> A ,and
>>> network
>>> >>>> 6-10 are served through router B like HSRP though multiple
>>> stand-by
>>> >>>> group,
>>> >>>> and for load balancing both devices are actively serving the
>>> >>>> networks
>>> >>>> 1-10
>>> >>>> like GLBP.
>>> >>>>
>>> >>>> Regards,
>>> >>>> Zaid
>>> >>>>
>>> >>>>
>>> >>>> -----Original Message-----
>>> >>>> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On
>>> Behalf
>>> Of
>>> >>>> Pavel Bykov
>>> >>>> Sent: 07 July 2009 10:59
>>> >>>> To: jack daniels
>>> >>>> Cc: Cisco certification
>>> >>>> Subject: Re: Load balancing
>>> >>>>
>>> >>>> for routining, equal cost routes are simultaneously
>>> installed in >>>> CEF.
>>> >>>> CEF then load balances to what is predefined. Normally, it's
>>> SRC/DST
>>> >>>> pair
>>> >>>> what makes the hash.
>>> >>>> ip cef load-sharing
>>> >>>> command changes the method of balancing.
>>> >>>>
>>> >>>> Software platforms (800/1800/2800/3800/7200) also enable you
>>> to load
>>> >>>> balance
>>> >>>> per packet in routnd robin fasion.
>>> >>>> Then it's per interface command "ip load-sharing per-packet"
>>> >>>>
>>> >>>> Load sharing/balancing are similar terms which are not divided
>>> regarding
>>> >>>> particular feature.
>>> >>>> So you can refer to balancing as sharing and sharing to
>>> balancing.
>>> >>>>
>>> >>>>
>>> >>>> On Tue, Jul 7, 2009 at 9:47 AM, jack daniels >>>> <jckdaniels12_at_gmail.com
>>> >
>>> >>>> wrote:
>>> >>>>
>>> >>>> > Dear All,
>>> >>>> >
>>> >>>> > I'm very confused on the diffrent ways for load balancing the
>>> traffic
>>> >>>> if I
>>> >>>> > have more than one route in my routing table.
>>> >>>> >
>>> >>>> > Also please suggest diffrence between load sharing and load
>>> balancing
>>> >>>> >
>>> >>>> >
>>> >>>> > Regards
>>> >>>> > J.Daniels
>>> >>>> >
>>> >>>> >
>>> >>>> > Blogs and organic groups at http://www.ccie.net
>>> >>>> >
>>> >>>> >
>>> >>>>
>>> _______________________________________________________________________
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>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>> >
>>> >>>>
>>> >>>>
>>> >>>> --
>>> >>>> Pavel Bykov
>>> >>>> ----------------
>>> >>>> Don't forget to help stopping the braindumps, use of which
>>> reduces
>>> value
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>>> >>>> your certifications. Sign the petition at
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>>> >>>>
>>> >>>>
>>> >>>>
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>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>>
>>> >>>
>>> >>
>>> >>
>>> >> --
>>> >> Pavel Bykov
>>> >> ----------------
>>> >> Don't forget to help stopping the braindumps, use of which
>>> reduces >> value
>>> >> of your certifications. Sign the petition at
>>> >> http://www.stopbraindumps.com/
>>> >>
>>> >
>>> >
>>>
>>>
>>> --
>>> Pavel Bykov
>>> ----------------
>>> Don't forget to help stopping the braindumps, use of which reduces
>>> value of
>>> your certifications. Sign the petition at http://www.stopbraindumps.com/
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
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>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> <ruhann>
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
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>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at: http://www.groupstudy.com/list/CCIELab.html

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Received on Sat Jul 18 2009 - 18:47:33 ART