At 04:06 AM 6/1/97 -0400, Todd Graham Lewis wrote:
On Sun, 1 Jun 1997, Circuit wrote:
comments, rants, flames?
Do satellites really stand a chance against fibre? Most people think not, and more specifically that their competitiveness shall continue to decline as time progresses. Not exactly the kind of thing one wants to lay out large capital expenditures on...
High orbit, geosyncronous sattelites do not stand much of a chance against land lines as the latency on the links is quite high. Low orbit satellites, however, can be quite effective competition assuming that they have enough satellites to get coverage. These types of satellites are the ones that Gates is thinking of launching as well as several other companies/consortiums. When we can all have > 1MB/sec connectivity wireless to our laptops/video portable phones, with global coverage, satellites will rule the day. Justin "I still like land lines" Newton Justin W. Newton Senior Network Architect Priori Networks http://www.priori.net ISP/C, Director at Large http://www.ispc.org
High orbit, geosyncronous sattelites do not stand much of a chance against land lines as the latency on the links is quite high. [...]
Long latency is not automatically bad. It is bad for interactive traffic, but if the bandwidth is high enough to reduce congestion to zero, a large latency doesn't hurt bulky transfers at all. Netnews, for example, could be distributed via satellite without hurting anybody's lookers or feelers.
You can always have compartively small land lines to handle burst traffic. And the bulk of the data [lower priority] over the satellite links. [Similar to the way Oracle handles interactive video over cable.] -Deepak. On Sun, 1 Jun 1997, Paul A Vixie wrote:
High orbit, geosyncronous sattelites do not stand much of a chance against land lines as the latency on the links is quite high. [...]
Long latency is not automatically bad. It is bad for interactive traffic, but if the bandwidth is high enough to reduce congestion to zero, a large latency doesn't hurt bulky transfers at all. Netnews, for example, could be distributed via satellite without hurting anybody's lookers or feelers.
According to Paul A Vixie:
High orbit, geosyncronous sattelites do not stand much of a chance against land lines as the latency on the links is quite high. [...]
Long latency is not automatically bad. It is bad for interactive traffic, but if the bandwidth is high enough to reduce congestion to zero, a large latency doesn't hurt bulky transfers at all. Netnews, for example, could be distributed via satellite without hurting anybody's lookers or feelers.
And with the push to use multicast across such high latency links, you can get better dessimination of some types of data which involve many sites within a satellite's foot print (e.g. nntp, ftp mirroring, db syncronization). There also is a new proposed spec for doing FTP using multicasting (MFTP - multicast FTP) which has been tested using some INTELSAT birds with good results. MFTP has also the characteristic of reduced sensitivity to long latency, but also to the bit error rate (BER) which is also a problem when using satellites. --curtis -- Curtis Generous generous@uucom.com Phone: (703) 461-1350 UUcom Inc., Suite 250, 4875 Eisenhower Avenue, Alexandria, VA 22304-0797
Hi, Curtis Generous wrote:
And with the push to use multicast across such high latency links, you can get better dessimination of some types of data which involve many sites within a satellite's foot print (e.g. nntp, ftp mirroring, db syncronization).
Or broadcasted web caching - people who subscribe get daily updates to their favorite sites.
There also is a new proposed spec for doing FTP using multicasting (MFTP - multicast FTP) which has been tested using some INTELSAT birds with good results. MFTP has also the characteristic of reduced sensitivity to long latency, but also to the bit error rate (BER) which is also a problem when using satellites.
Sounds good for push media, too --- without multicast, these will kill international links. -- miguel a.l. paraz <map@iphil.net> +63-2-893-0850 iphil communications, makati city, philippines <http://www.iphil.net>
Perhaps this is finally a case for those little TOS bits in an IP header? Interactive stuff like Telnet traffic could go through a slow land line, whereas bulk traffic could go via satellite. I'm not sure how many TCP/IP stacks still set those bits; it may be necessary to have a router manipulate the bits after examining the port numbers of a connection. FYI, Planet Connect (and others) has been offering Usenet feeds via 18" dish for quite some time now. Stephen At 14:33 01-06-97 -0700, Paul A Vixie wrote:
High orbit, geosyncronous sattelites do not stand much of a chance against land lines as the latency on the links is quite high. [...]
Long latency is not automatically bad. It is bad for interactive traffic, but if the bandwidth is high enough to reduce congestion to zero, a large latency doesn't hurt bulky transfers at all. Netnews, for example, could be distributed via satellite without hurting anybody's lookers or feelers.
Hi, Stephen Sprunk wrote:
I'm not sure how many TCP/IP stacks still set those bits; it may be necessary to have a router manipulate the bits after examining the port numbers of a connection.
Looks like a good place to use access lists that choose packets based on tcp, udp, and port number. If I could get a 45 Mbps circuit over high-latency geosatellite, one-way, I could use it for http and "push" traffic. The requests, outbound stuff, and interactive traffic would fit into a T1 under the ocean. Cheers, -- miguel a.l. paraz <map@iphil.net> +63-2-893-0850 iphil communications, makati city, philippines <http://www.iphil.net>
participants (6)
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Curtis Generous -
Deepak Jain -
Justin W. Newton -
Miguel A.L. Paraz -
Paul A Vixie -
Stephen Sprunk