> ## Documentation Index
> Fetch the complete documentation index at: https://docs.megaport.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MCR Route Summarization

> This help topic describes how you can achieve a similar outcome to route summarization on MCR.

export const Gloss = ({term, anchor, langDir = 'en'}) => {
  const errorPrefix = '\x1b[31;1;4mERROR\x1b[0m: Gloss -';
  if (typeof term !== 'string') {
    term = String(term);
  }
  if (typeof anchor !== 'string') {
    anchor = String(anchor);
  }
  if (!term || term === 'undefined') {
    console.error(`${errorPrefix} the \`term\` property is required — rendering an empty string instead`);
    return <></>;
  }
  if (!anchor || anchor === 'undefined') {
    console.error(`${errorPrefix} the \`anchor\` property is required — rendering an empty string instead`);
    return <></>;
  }
  const lang = langDir === 'en' ? '/' : '/' + langDir + '/';
  const glossaryPage = lang + 'glossary/#' + anchor;
  return <a href={glossaryPage}>{term}</a>;
};

export const Image = ({src, alt = '', caption, width, height, shadow}) => {
  const errorPrefix = '\x1b[31;1;4mERROR\x1b[0m: Image -';
  if (typeof src !== 'string') {
    src = String(src);
  }
  if (!src || src === 'undefined') {
    console.error(`${errorPrefix} \`src\` is required — rendering an empty string instead`);
    return <></>;
  }
  const img = <img className={['mega-image-style', shadow ? 'shadow' : ''].join(' ')} src={src} alt={alt} width={width} height={height} style={{
    display: 'block'
  }} />;
  return caption ? <figure>
      {img}
      <figcaption style={{
    textAlign: 'center',
    width
  }}>{caption}</figcaption>
    </figure> : img;
};

This topic describes how you can achieve a similar outcome to route summarization on MCR using a combination of static routes and filtering. This will help avoid the situation where CSP limits are being reached due to the number of routes being advertised.

This image shows how route summarization could be configured, with the customer-facing VXC originating several prefixes but where you want to advertise only a summary route to the CSP.  <br />

<Image src="/images/mcr/mcr-route-summary.png" alt="This image shows how route summarization could be configured, with the customer-facing VXC originating aseveral prefixes but where you want to advertise a summary route to the CSP." shadow={true} width={800} />

If you configure a static <Gloss term="supernet" anchor="supernet" /> on the VXC facing the source of the smaller networks, this will cause the MCR to also advertise the supernet to the CSP. You can then use prefix filters to not advertise the specifics to the CSP which will achieve approximately the same behavior as route summarization.

## Helpful references

* [Creating an MCR VXC](/mcr/mcr-vxc)
* [Filtering by BGP prefix](/mcr/route-filtering#bgpprefixfilter)
* [Introduction to Route Summarization](https://networklessons.com/rip/introduction-route-summarization)
* [Route Summarization](https://networklessons.com/subnetting/route-summarization)