[THIN] Re: Session Reliability
- From: Saravanan Srinivasan <sarav2k@xxxxxxxxx>
- To: thin@xxxxxxxxxxxxx
- Date: Sun, 18 Jan 2009 09:27:09 -0800 (PST)
Another reason we found is Access Gateway's High Availability pair needs
Session Reliability for ica sessions fail-over.
--- On Sat, 1/17/09, Steve Greenberg <steveg@xxxxxxxxxxxxxx> wrote:
> From: Steve Greenberg <steveg@xxxxxxxxxxxxxx>
> Subject: [THIN] Re: Session Reliability
> To: thin@xxxxxxxxxxxxx
> Date: Saturday, January 17, 2009, 9:58 AM
> I agree with Rick- Session Reliability is recommended when
> you have a known
> situation of recurring short term disconnects. However it
> may not be a
> benefit to turn on "just because". As Rick
> explains it does not really make
> sessions more reliable, it just presents a less frustrating
> appearance
> during the period of time the session is off line and is
> trying to
> re-connect.
>
>
>
>
>
>
>
> Steve Greenberg
>
> Thin Client Computing
>
> 34522 N. Scottsdale Rd D8453
>
> Scottsdale, AZ 85266
>
> (602) 432-8649
>
> www.thinclient.net
>
> steveg@xxxxxxxxxxxxxx
>
>
>
> _____
>
> From: thin-bounce@xxxxxxxxxxxxx
> [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf
> Of Rick Mack
> Sent: Friday, January 16, 2009 11:53 PM
> To: thin@xxxxxxxxxxxxx
> Subject: [THIN] Re: Session Reliability
>
>
>
> Hi Angela,
>
>
>
> The concept behind session reliability is to hide the
> disconnect/reconnect
> event from users. It doesn't actually improve things
> for your users, but
> instead of their sessions disconnecting and reconnecting,
> the session just
> appears to hang for a bit and then starts again. Session
> reliability is
> actually a really bad name for this enhancement because it
> doesn't do what
> it implies.
>
>
>
> Session reliability is functionally a wrapper for standard
> ICA that
> encapsulates the ICA protocol and allows you to handle
> stuff like
> transparent session reconnection. However it uses a
> different port to ICA,
> TCP port 2598. The session reliability listener is the
> Citrix XTE service
> which then passes the ICA traffic on to the ICA listener.
>
>
>
> So far so good, but there are 2 potential problems.
>
>
>
> The first is that the XTE service hasn't been totally
> stable in the past
> with recurring instances of memory leaks and instability
> depending on hotfix
> levels. If the XTE service starts playing up, session
> reliability just
> became your worst enemy.
>
>
> The second problem relates to the use of a different TCP
> port. It's fairly
> common these days to set network QOS to favour ICA traffic
> when you use
> Citrix. Everyone, especially your average comms person,
> knows that ICA is on
> TCP port 1494 and that is what is used to identify ICA
> packets for QOS
> prioritization.
>
>
>
> When you switch on session reliability you are no longer
> using port 1494. So
> any QOS optimization you've got for ICA suddenly
> disappears, and in a worst
> case scenario, session performance can go out the door, you
> start seeing a
> lot more disconnections and session reliability becomes
> "session liability".
>
>
>
> However if your users are suffering a reasonable number of
> disconnections
> and that is creating annoyance and political problems for
> you, then by all
> means investigate using session reliability. But make sure
> that if you are
> using QOS, that you co-ordinate with your comms people and
> ISP so that when
> you enable session reliability nothing will break. Make
> absolutely certain
> that they know ICA can use port 1494 AND port 2598.
>
>
>
> And good luck :-)
>
>
>
> regards,
>
>
>
> Rick
>
>
>
> --
> Ulrich Mack
> Quest Software
> Provision Networks Division
>
> On Sat, Jan 17, 2009 at 1:28 PM, Angela Smith
> <angela_smith9@xxxxxxxxxxx>
> wrote:
>
> Hi
>
> Im looking at enabling session reliability on my CPS 4
> farm. Are there any
> gotchas I need to be aware of or could this cause more
> issues? Im aware of
> the port changes but I wanted to know if most people are
> using this or
> whether session performance is slower due to the additional
> connection
> checks..
>
> Thanks
> Angela
>
> _____
>
> Download free emoticons today! Holiday
> <http://livelife.ninemsn.com.au/article.aspx?id=669758>
> cheer from
> Messenger.
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