Re: [load balancing] Problem in pop3 connection

From: simon bullen (Simon.BullenIZZATSun.COM)
Date: Thu Jan 22 2004 - 04:04:30 EST

  • Next message: John Hall: "Re: [load balancing] Load Balancer Evaluation: Which would you pick?"

    Manish,

    Try upping the fastage and slowage settings on the AD3.

    This will stop the slow sessions being flushed from the arp tables.

    Regards

    Simon.

    Manish Verma wrote:
    >
    > Hi ,
    >
    > I am using Alteon AD3 , I am facing the problem establishing the POP
    > connection on slow links .When ever i access POP on Slow link i always get
    > the error:
    >
    > : Your server has unexpectedly terminated the connection. Possible causes
    > for this include server problems, network problems, or a long period of
    > inactivity. Subject '', Account: Server: , Protocol: SMTP, Port: 25,
    > Secure(SSL): No, Socket Error: 10054, Error
    >
    > If this is the known problem pl let me know what all settings could be done
    > on the alteon to resolve the problem.
    >
    > Regds
    > Manish
    >
    > ----- Original Message -----
    > From: "Shawn Nunley" <shawnIZZATnunleys.com>
    > To: <lb-lIZZATvegan.net>
    > Sent: Thursday, January 22, 2004 7:40 AM
    > Subject: RE: [load balancing] Load Balancer Evaluation: Which would you
    > pick?
    >
    > > John,
    > >
    > > Just to be clear, the NetScaler device does not ever send connections
    > > 'through' ANY OS, ever. The performance effects of doing this would be
    > > catastrophic and would not allow us to support the speeds and feeds we
    > > advertise. Everything is handled within our packet engine which
    > > communicates directly with RAM, NICs and the CPU, all in kernel mode with
    > no
    > > context switching to slow things down.
    > >
    > > The difference is worth pointing out since we spent years developing that
    > > technology in order *not* to be lumped in with devices that are limited by
    > > generic OS TCP/IP stacks. Nothing personal, but I couldn't let that
    > > generalization just slip by.
    > >
    > > BTW, I hope you're having a great New Year.
    > >
    > > -Shawn
    > >
    > > -----Original Message-----
    > > From: John Hall [mailto:j.hallIZZATf5.com]
    > > Sent: Wednesday, January 21, 2004 12:44 PM
    > > To: lb-lIZZATvegan.net
    > > Subject: Re: [load balancing] Load Balancer Evaluation: Which would you
    > > pick?
    > >
    > >
    > > It would be interesting to find out what engineer said this, but it is
    > > essentially incorrect. Recent BIG-IP's that have our Packet Velocity
    > > ASIC (you gotta love marketing folks) have a range of load balancing
    > > options including full hardware acceleration (the entire connection is
    > > handled by the ASIC with no host processor support required) through
    > > partial acceleration (the connection is initially handled by software,
    > > but as soon as a load balancing decision is made, it's handed off to the
    > > ASIC for the rest of the connection), to full software load balancing
    > > which provides all the possible load balancing capabilities.
    > >
    > > In regards to the original question. I strongly suggest that you ask
    > > the top several vendors on your list specifc questions about your
    > > planned (and future) load profile. All of the boxes you are looking at
    > > have a host processor running some OS (vxWorks, BSD, BSDI, etc) and all
    > > of them send some types of connections to the host processor for
    > > handling. The loads you are planning are significantly above the
    > > capabilities of some of the boxes you list to handle in software, but
    > > are probably quite easily handled in a partially or fully hardware
    > > accelerated modes. Specific characterization of your load profile and
    > > some direct questions to the vendors should help you narrow down your
    > > choices.
    > >
    > > An illustrative anecdote involves the effect of the Nachi worm on
    > > several vendors of six-figure cost layer 2/3 switches. Many of the
    > > vendors sent ICMP packets to the switches host processor for handling
    > > and their host processors are often amazingly low powered, so a single
    > > Nachi infected PC sending ICMP packets to thousands of random
    > > destinations could bring these very expensive and capable switches to
    > > their knees. Some switches handled ICMP in hardware, but updated their
    > > ARP tables using the host processor and they were incapacitated by ARP
    > > updates. So, while these switches quite ably handled the "normal" layer
    > > 2/3 load, they were crippled by an unusual (but perfectly "legal", at
    > > least according to the RFC's) load profile that their designers did not
    > > anticipate.
    > >
    > > JMH
    > >
    > > Mike W wrote:
    > >
    > > > Radware is a switch based solution, while F5 is still a unix kernel
    > > > based product, which some say takes them out of the "switch market" -
    > > > their marketing discusses their network processor, but one of there
    > > > engineers at a trade show last year finally admitted when pressed,
    > > > that they didn't use it when doing actual load balancing, only if they
    > > > were a router.
    > >
    > > --
    > > John Hall Test Manager - Switch Team F5 Networks,
    > > Inc.
    > >
    > > ____________________
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    > >
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