Re: Router ID in OSPF
thanks for all your help "Howard C. Berkowitz" <[EMAIL PROTECTED]> wrote in message news:p05001902b669209cb2e1@[63.216.127.98]... > >Hi everybody: > >I am study BSCN,there are something confused me: > >in the book they says:The highest IP address on an active interface is > >normally used as the router ID, but this can be overridden by configuring an > >IP address on a loopback interface. > >I want to know which will be the Router ID if the loopback IP address > >smaller than the active interface IP address? > >Any suggestion will be appreciate,thanks. > > > >Will Guan > >frome Peking, China > > > If there are multiple loopback, the router ID will be the numerically > highest IP address on any loopback. In other words, > > int loop 0 int loop 1 int loop 2 > ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 > > The router ID, in this case, was 5.6.7.8. > > If there is only a single loopback interface, its IP address will > always be the router ID: > > int loop 0 int ser 0 int ser 1 > ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 > > Here, the router ID would be 1.2.3.4. > > If there were no loopback interfaces, the numerically highest active > interface would be used: > > int eth 0 int ser 0 int ser 1 > ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 > no shutdown shutdown no shutdown > > 2.3.4.6 would be the router ID. > > > _ > FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Router ID in OSPF
Only when the reloading the router or doing copy/paste no router ospf id, then router ospf id >From: Marty Adkins <[EMAIL PROTECTED]> >Reply-To: Marty Adkins <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >CC: "Howard C. Berkowitz" <[EMAIL PROTECTED]> >Subject: Re: Router ID in OSPF >Date: Fri, 22 Dec 2000 11:01:35 -0500 > >"Howard C. Berkowitz" wrote: > > > > >Hi everybody: > > >I am study BSCN,there are something confused me: > > >in the book they says:The highest IP address on an active interface is > > >normally used as the router ID, but this can be overridden by >configuring an > > >IP address on a loopback interface. > > >I want to know which will be the Router ID if the loopback IP address > > >smaller than the active interface IP address? > > >Any suggestion will be appreciate,thanks. > > > > > >Will Guan > > >frome Peking, China > > > > If there are multiple loopback, the router ID will be the numerically > > highest IP address on any loopback. In other words, > [snip] >And the part that some folks forget is that once a router ID is active, >it will not change if another interface is made active, or the IP of >another interface is changed to a higher value. The rationale is >stability, since all other routers in the area are tracking this one >by its present router ID. The same principle applies to the DR election >-- there is no coup option. > >Now if you were to shut down the interface with the existing router ID... > > Marty Adkins Email: [EMAIL PROTECTED] > Mentor Technologies Phone: 410-280-8840 x3006 > 275 West Street, Plaza 70WWW: http://www.mentortech.com > Annapolis, MD 21401 Cisco CCIE #1289 > >_ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _ Get your FREE download of MSN Explorer at http://explorer.msn.com _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Router ID in OSPF
"Howard C. Berkowitz" wrote: > > >Hi everybody: > >I am study BSCN,there are something confused me: > >in the book they says:The highest IP address on an active interface is > >normally used as the router ID, but this can be overridden by configuring an > >IP address on a loopback interface. > >I want to know which will be the Router ID if the loopback IP address > >smaller than the active interface IP address? > >Any suggestion will be appreciate,thanks. > > > >Will Guan > >frome Peking, China > > If there are multiple loopback, the router ID will be the numerically > highest IP address on any loopback. In other words, [snip] And the part that some folks forget is that once a router ID is active, it will not change if another interface is made active, or the IP of another interface is changed to a higher value. The rationale is stability, since all other routers in the area are tracking this one by its present router ID. The same principle applies to the DR election -- there is no coup option. Now if you were to shut down the interface with the existing router ID... Marty Adkins Email: [EMAIL PROTECTED] Mentor Technologies Phone: 410-280-8840 x3006 275 West Street, Plaza 70WWW: http://www.mentortech.com Annapolis, MD 21401 Cisco CCIE #1289 _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Router ID in OSPF
>Hi everybody: >I am study BSCN,there are something confused me: >in the book they says:The highest IP address on an active interface is >normally used as the router ID, but this can be overridden by configuring an >IP address on a loopback interface. >I want to know which will be the Router ID if the loopback IP address >smaller than the active interface IP address? >Any suggestion will be appreciate,thanks. > >Will Guan >frome Peking, China If there are multiple loopback, the router ID will be the numerically highest IP address on any loopback. In other words, int loop 0 int loop 1 int loop 2 ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 The router ID, in this case, was 5.6.7.8. If there is only a single loopback interface, its IP address will always be the router ID: int loop 0 int ser 0 int ser 1 ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 Here, the router ID would be 1.2.3.4. If there were no loopback interfaces, the numerically highest active interface would be used: int eth 0 int ser 0 int ser 1 ip addr 1.2.3.4 ip addr 5.6.7.8 ip addr 2.3.4.6 no shutdown shutdown no shutdown 2.3.4.6 would be the router ID. _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: Router ID in OSPF
Hi, The loopback IP address configured will be the Router ID even if it is less than the IP address on the active interface. This is because the loop back interface will not go down as the physical interface. Raghavan At 02:24 PM 12/22/00 +0800, you wrote: >Hi everybody: >I am study BSCN,there are something confused me: >in the book they says:The highest IP address on an active interface is >normally used as the router ID, but this can be overridden by configuring an >IP address on a loopback interface. >I want to know which will be the Router ID if the loopback IP address >smaller than the active interface IP address? >Any suggestion will be appreciate,thanks. > >Will Guan >frome Peking, China > > >_ >FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Router ID in OSPF
Hi everybody: I am study BSCN,there are something confused me: in the book they says:The highest IP address on an active interface is normally used as the router ID, but this can be overridden by configuring an IP address on a loopback interface. I want to know which will be the Router ID if the loopback IP address smaller than the active interface IP address? Any suggestion will be appreciate,thanks. Will Guan frome Peking, China _ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
