At 1:40 AM +0000 1/8/03, The Long and Winding Road wrote: >""William Li"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >> Hi group >> >> >> >> I just happened to find there is an advertise option could be added >> in "area area-id range ip-address mask" command. The command could be >> like this "area area-id range ip-address mask advertise". My question >> is, will there be any functional difference between with and without >> this option. As per DOC CD, option "advertise" means: Sets the address >> range status to advertise and generates a Type 3 summary link-state >> advertisement (LSA). But by default, when we generate a summary address >> in ABR without any options, the summary address will be advertised >> automatically, am I right? > > >you are correct. > >if it is any help, Parkhurst states that the two commands area x range and >area x range advertise are equivalent. >there is no difference in behaviour that I have determined in my own humble >experiments.
Historically, when Cisco is thinking of changing a default, the show config commands will start displaying the current default (either xxx or no xxx). Later, a command to change the default will be made available, and the show command will show however the option is set. Eventually, the new default will stop displaying unless an explicit command is configured. Now, there are two ways I've seen an ABR behave when some of the more-specifics of a summary disappear from the LSDB. On Cisco, the summary continues to be advertised. This increases black-holing but also improves stability. In Bay/Wellfleet/Nortel RS, if some more-specifics disappear, the ABR stops advertising the summary and only passes the available more-specifics. This technique does avoid blackholes but causes more churn. Both interpretations/implementations have valid applications, and I've always wished Cisco supported both. I wonder if we have seen a slightly warped command release strategy here, and there is a conditional "no-advertise" in the works that will allow the Nortel-like behavior as well as the Cisco behavior. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=60571&t=60550 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
