DRAM and Flash memory are related with running BGP?

[ohforce55]

Hi,

I was told to upgrade DRAM and Flash memories for the C3825 router I have in order to run BGP without issue.

How are those related with running BGP?

Can you please explain?

What needs to be upgraded and What do I have to check in order to configure and run BGP in router?

Below is the sh ver of the router.

Bold parts are DRAM 785M  and Flash 125M.

Router#sh ver

Cisco IOS Software, 3800 Software (C3825-ADVIPSERVICESK9-M), Version 15.1(4)M10, RELEASE SOFTWARE (fc2)

Technical Support: http://www.cisco.com/techsupport

Copyright (c) 1986-2015 by Cisco Systems, Inc.

Compiled Tue 24-Mar-15 09:50 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T11, RELEASE SOFTWARE (fc1)

USWP-BRDRTR-01 uptime is 16 minutes

System returned to ROM by power-on

System image file is "flash:c3825-advipservicesk9-mz.151-4.M10.bin"

Last reload type: Normal Reload

This product contains cryptographic features and is subject to United

States and local country laws governing import, export, transfer and

use. Delivery of Cisco cryptographic products does not imply

third-party authority to import, export, distribute or use encryption.

Importers, exporters, distributors and users are responsible for

compliance with U.S. and local country laws. By using this product you

agree to comply with applicable laws and regulations. If you are unable

to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:

http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to

export@cisco.com.

Cisco 3825 (revision 1.2) with 686080K/100352K bytes of memory.

Processor board ID FTX1324A1TP

2 FastEthernet interfaces

2 Gigabit Ethernet interfaces

1 Serial interface

1 Virtual Private Network (VPN) Module

1 Subrate T3/E3 port

DRAM configuration is 64 bits wide with parity enabled.

479K bytes of NVRAM.

125440K bytes of ATA System CompactFlash (Read/Write)

[Georg Pauwen]

Hello,

you have plenty of DRAM to run BGP. The only reason you would need to upgrade would be if you are a transit AS and would need to receive the full BGP routing table (roughly 670K prefixes currently). ?

What are you trying to set up, eBGP with an ISP ?

[ohforce55]

Hi,

Thank you for your reply. So can you please tell me what DRAM does and how can I decide how much memory I need?

I'm not exactly sure what we will do with the router yet.

Thank you!

[Georg Pauwen]

Hello,

DRAM holds the BGP RIB (Routing Information Base). There is no exact way to calculate how much you need, but as stated, 750MB is plenty to run BGP. That said, 1GB is the maximum for the 3825 anyway.

[ohforce55]

Thank you so much Georg!

[ohforce55]

As mentioned before the DRAM memory on my router is 785M. I found another DRAM memory 256M online. Is it possible to attach the additionally DRAM so I can make it over 1 GM? Or can only one DRAM be attached to the router?

[Georg Pauwen]

Hello,

your DIMMs need to be of equal size. That said, your options are 128, 256, or 512. In order to get to 1024, you need 512x2. The 3825 has two DRAM slots.

[ohforce55]

Thank you for your reply!

So one 128 and one 256 cannot be attached at the same time correct?

They have to be the same type of memory size?

I wonder how my DRAM memory is 750MB....

[Georg Pauwen]

Hello,

your DRAM is exactly 768. Which can only mean 512 + 256...

Which contradicts what I said about the DIMMs having to be the same size...

Either way, you have two slots, so you need another 512 DRAM module...

[Joseph W. Doherty]

As Georg has noted, RAM is used to hold routing information, so as it grows, so does your need for RAM.  Normally on new routers you rarely run into insufficient RAM, except when working with Internet routing.

As to flash, that holds the IOS software.  Some IOS versions that support BGP are bigger require a larger flash to store them on your device.  However, it's easy to compare flash capacity with IOS file size.

[ohforce55]

Thank you Joseph! Really helpful!

[ohforce55]

As mentioned before the DRAM memory on my router is 785M. I found another DRAM memory 256M online. Is it possible to attach the additionally DRAM so I can make it over 1 GM?