AD replication latency & required bandwidth question

hi, i've following scenario:

office site: ad server (2nd ad, gc)

data centre site: ad server (1st ad, gc), exchange 2010 server placed in.

number of users:

office: 20 - 30 users

data centre site: n/a

to guarantee success replication, know round-trip latency limit , required bandwidth. thanks.

curious, have such small user base. concerned slow link? have slow link @ 1 or other location? line speed - t1, t3, mpls, cable, fios, dsl, adsl, t3, etc? @ both offices? location lowest bandwidth common denominator.

this broad topic. 100ms acceptable limit. far bandwidth, 512 kbps or lower considered "slow." if below 128 kbps, must use smtp replication, requires separate domains on each side because it's slow replicate domain blob data.

keep in mind, authentication packet size alone between 512kb 1mb in size group policy & other apps requires bandwidth on 512kbps, why if absolute wan speed between locations below speed, such remote vpn users on slow link, the security settings of gpo apply.

the best way think determine bandwidth requirements given, rather current scenario, such yours, run packet captures record traffic bandwidth between 2 sites, or use sort of bandwidth tracking software. choose depend on firewalls - run on routers/firewalls, or run netboy on server/pc plugged hub (not switch) between company main switch , firewall.

bandwidth monitor pro - monitor bandwidth!\
http://www.bandwidthmonitorpro.com/

here's more info ad branch designs:

detailed branch office deployment guide
http://www.microsoft.com/downloads/details.aspx?familyid=9353a4f6-a8a8-40bb-9fa7-3a95c9540112&displaylang=en

[is there an] active directory sizing tool windows 2008 r2 [?]
http://social.technet.microsoft.com/forums/en-us/winserverds/thread/48e9c9ac-468e-45cc-8328-5316788386a6

 

 

it's suggested no use adsl line due pppoe mtu of 1492. it negates/affects ad rpc/ldap commuications. satelite introduces high latency. in cases, cable, too, if there more 15 hops (i've seen cable installations 19-20 hops website).

also, if concerned slow line speed, must factor various items that affect usable bandwidth may affect ad replication, such as:

• user use concurrency (how many performing network traffic tasks - outlook, calendaring, public folders (real-time),
• internet use traffic (user , mail traffic)
• outlook/exchange traffic (cached mode saves bandwidth)
• if users send large attachments
• allowing users use watch youtube videos, streaming videos, streaming music, etc (this drastically reduce available bandwidth)

 

you may want take @ design ipd guide ad - download details: ipd guide active directory domain services – version 2.0
http://go.microsoft.com/fwlink/?linkid=160829

 

here of notes on latency (it falls under multiple subjects):

==========
there network latency, ad replication latency, , exchange 2010 dag replication latency.

active directory replication latency
"the local domain controller has not received replication information number of domain controllers within configured latency interval ... can use support tool repadmin.exe display replication latencies of domain controllers in forest.
http://www.nwsmith.net/hintstips/ad-replication-latency.htm

storage virtualization | faqs & discussions - dr , asynchronous replication - tutorial , best practices
link discusses lan storage solutions in regards virtualization, , how bandwidth affects it, , if round trip latency high, want use asynchronous vs synchronous replication. has bandwidth chart, too.
http://www.las-solanas.com/storage_virtualization/asynchronous_replication.php

exchange 2010 - planning high availability , site resilience
applies to: exchange server 2010 sp1 - topic last modified: 2011-02-02
http://technet.microsoft.com/en-us/library/dd638104.aspx

 

ace

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ace fekay
mvp, mct, mcitp ea, mcts windows 2008 & exchange 2007 & exchange 2010, exchange 2010 enterprise administrator, mcse & mcsa 2003/2000, mcsa messaging 2003
microsoft certified trainer
microsoft mvp - directory services
complete list of technical blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php

this posting provided as-is no warranties or guarantees , confers no rights.

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