Scenario Coming UP Soon 2

[thule]

I have an 8510 MSR bring in my internet connection on

Port 0/7
IP 68.95.xxx.XX1/128 mask

It directly connects at this time to a PIX 525 with an adjacent IP 68.95.xxx.xx2/128 mask

We are bringing in a 3725 Router will have an 8 port ATM blade that will connect to a PVC to another campus for direct link and the standard two ethernet ports

ATM Port 1
IP 161.xxx.xxx.xxx

Question:

I need to take the 8510 and connect it to one of the 3725 ethernet ports.
Then I need to come out of the other ethernet port into the pix outside port.

The pix will require an IP on the outside interface
I am assuming both the ethernet ports on the 3725 will also need an ip address. Can you assign both ethernet ports an IP in the same range without causing problems? Or, can you simply not assign IP to the 3725 ethernet ports and use it like a switch.

I have a feeling this setup is going to trash my settings to the ISP because it is going to need to be subnetted further down.

Thanks for any input you can provide.

 

[Narizz28]

While I've never used an 8510, I have tried to assign two ehternet ports to the same network with luck only once. Just assigning them with an address and the same subnet mask in the same network will give you an address overlap error. In my scenario, both interfaces were on a /24 network with one needing to talk to a .110 address, and the other to .2 address. What I ended up doing was calculating the exact binary address of the .110 and under it, writing the binary address of .2

0 1 1 0 1 1 1 0 =110 on the 4th octet
0 0 0 0 0 0 1 0 =2

Armed with this, I started calculating that hosts available with different subnet masks. Ended up going with a /28 mask, as it woulod split the host bits as such:

0 1 1 0 | 1 1 1 0 (110)
0 0 0 0 | 0 0 1 0 (2)

From there I found all the possible host addresses in each subnet (don't forget that the host bits cannot be all 1's or 0's) and came up with 97 through 110 on the high side, and 1 through 14 on the low side. I then found an open address in the /24 network within each range. .98 and .10 were open and available. I used .10 to get to .2 and .98 to get to .110 and set the netmask to /28.

Worked like a charm.

 

[thule]

Thanks, I will keep this in the planning stage and submit it to the rest of the team that is working on this project. This one has had me stumped to no end.

 

[gconnect]

you maybe, just maybe able to get away with assigning an IP address to the first interface using 'ip unnumbered' on the other or even possibly using a Bridged Virtual Interface (BVI)

BVI or Intergrated Routing and Bridging will probably work,...........cross your fingers
don't give the interfaces ips but assign them to a 'bridge-group', then define a logical interface that corresponds to that bridge-group (like VLAN'ing)

http://www.cisco.com/en/US/products...s_configuration_example09186a008009413b.shtml

take away the atm stuff and just apply the bridge group commands to the 2 FastEthernet interfaces on the 3725

http://www.cisco.com/en/US/products...figuration_guide_chapter09186a00800f0a86.html

http://www.cisco.com/en/US/products...figuration_guide_chapter09186a008007f229.html

-gC-
"All over the Internet

 

[gconnect]

also I have access to a 3725 and just logged in to make sure that it BVI is available
p.s. dont get excited about the 'interface range' command, it probably will not help out here.

XXXXXXX#confi t
Enter configuration commands, one per line.  End with CNTL/Z.
XXXXXXX(config)#interface ?
  Async              Async interface
**  BVI                Bridge-Group Virtual Interface ***
  CTunnel            CTunnel interface
  Dialer             Dialer interface
  FastEthernet       FastEthernet IEEE 802.3
  Group-Async        Async Group interface
  Loopback           Loopback interface
  MFR                Multilink Frame Relay bundle interface
  Multilink          Multilink-group interface
  Null               Null interface
  Port-channel       Ethernet Channel of interfaces
  Tunnel             Tunnel interface
  Vif                PGM Multicast Host interface
  Virtual-Template   Virtual Template interface
  Virtual-TokenRing  Virtual TokenRing
  XTagATM            Extended Tag ATM interface
  range              interface range command

******This is the code we are running*******

XXXXXXXX uptime is 17 weeks, 1 day, 33 minutes
System returned to ROM by power-on
System restarted at 18:37:02 CST Tue Dec 2 2003
***System image file is "flash:c3725-js-mz.123-5.bin"***

cisco 3725 (R7000) processor (revision 0.1) with 119808K/11264K bytes of memory.
Processor board ID JMX0743L0XL
R7000 CPU at 240MHz, Implementation 39, Rev 3.3, 256KB L2 Cache
Bridging software.
X.25 software, Version 3.0.0.
SuperLAT software (copyright 1990 by Meridian Technology Corp).
TN3270 Emulation software.
4 FastEthernet/IEEE 802.3 interface(s)
DRAM configuration is 64 bits wide with parity disabled.
55K bytes of non-volatile configuration memory.
31360K bytes of ATA System CompactFlash (Read/Write)

Configuration register is 0x2102

-gC-

 

[thule]

Thanks, I am reviewing this at home right now, but in the morning I will print these out and start writing a scenario to give my boss. Keep the suggestions coming, I really really do appreciate any and all of them.